SkatterBencher #43: AMD Ryzen Threadripper “5990X” Overclocked to 4825 MHz

skatterbencher #43 5990x

We overclock the AMD Ryzen Threadripper “5990X” up to 4825 MHz with using the ASUS ROG Zenith II Extreme Alpha and EK-Quantum water cooling.

To be more precise, though, we’re overclocking an early engineering sample CPU that we assume was supposed to end up being the successor to the Ryzen Threadripper 3990X. But as you undoubtedly know, AMD did not end up releasing the consumer versions of the Zen 3 Threadripper processors.

Since this is an early engineering sample of an unreleased CPU, I’ll try to cover the overclocking challenges as comprehensively as possible. This is undoubtedly the most powerful system I’ve ever laid my hands on, so I hope you enjoy the article!

AMD Ryzen Threadripper “5990X”: Introduction

First of all, the AMD Ryzen Threadripper 5990X doesn’t exist.

While AMD announced the Ryzen Threadripper Pro 5000 WX series processors on March 8, 2022, it never launched the consumer variants of Zen 3 Threadripper. However, that doesn’t mean AMD never planned for them.

Over the past few months, I’ve gathered information on the elusive consumer Threadripper 5000 processors. Based on my findings, early engineering samples were available and tested by AMD board partners back in June 2021. Validation samples of the final silicon were supposed to be available in September 2021, with the formal product launch one or two months later. However, those validation samples never arrived at the board makers, and, as we now know, the product launch never took place.

Zen 3 ryzen threadripper 5990X timeline

Instead, it appears AMD scrapped the consumer variants of Threadripper 5000 entirely and decided to focus exclusively on the Threadripper WX product line. More on that later, but first, let’s briefly cover the Threadripper origin story

As the story goes, the original Ryzen Threadripper was greenlit by AMD executives despite “having no business plan other than making something that was awesome.” The Threadripper slid in between the 8-Core Ryzen 7 1800X and the 32-Core EPYC 7601 in core counts and effectively completed AMD’s industry-disrupting product lineup.

At the end of the day, however, businesses need to make money. While the original Ryzen Threadripper was positioned as the ultimate platform for PC Enthusiasts, gaming performance was somewhat troublesome. In addition, AMD realized that the business case for Ryzen Threadripper lies not with gamers or enthusiasts, as up-market from Ryzen, but rather with professional workloads, as down-market from EPYC.

And thus, the slow repositioning of the Ryzen Threadripper product line began.

The Threadripper WX product was first introduced in 2018 when AMD announced the 2nd generation Ryzen Threadripper processors. AMD tried to clearly separate the X series from the WX series:

  • WX is designed for creators and innovators, whereas the X series is for enthusiasts and gamers
  • WX series get up to 4 CCDs and 32 cores, whereas X series get up to 2 CCDs and 16 cores
  • WX series has a TDP of 250W, whereas the X series has a TDP of 180W
  • However, fortunately, both WX and X series were compatible with consumer X399 chipset motherboards

The next-generation Ryzen Threadripper took that segmentation one step further as consumer Threadripper and professional Threadripper Pro processors have their own socket and chipset.

Together with the Zen 2-based Ryzen Threadripper processors, AMD introduced Socket TRX4. TRX4 is the direct successor to, and mechanically compatible with, the TR4 socket used for the first and second-generation Threadrippers. However, it is electrically incompatible, meaning third-generation Threadripper requires a new motherboard.

Unlike their SP3 server counterparts, TRX4 processors require a chipset to work. On November 25, 2019, AMD announced the Ryzen Threadripper 3990X – the world’s first 64-core consumer processor to accompany the TRX40 chipset.

In July 2020, AMD launched the Threadripper Pro WX processors series, which requires the WRX8 chipset and WRX80. The Threadripper Pro WX line is much more clearly a down-market equivalent of the EPYC server processors as they offer the same 8-channel memory and 128 PCIe lanes.

That brings us back to the Zen 3-based Ryzen Threadripper 5000 series we discussed earlier. While both consumer and professional variants were on roadmaps originally, in the end, AMD decided to only launch the professional Ryzen Threadripper Pro WX product line.

We can only speculate about the exact reasons why this decision was made. Linus Tech Tips did an excellent job of summing up the possible causes. They range from the evil profit-greedy corporation argument to DIY enthusiast high-end desktop just not making business sense anymore.

We can add the pandemic-related supply chain constraints, surge in PC demand, and lack of competition in this segment.

In short, the business case becomes evident if there’s no need to refresh the high-end desktop, and you can use the Zen 3 chiplets for high-in-demand products.

However, as Linus points out correctly, the Threadripper series also provide AMD with low-hanging marketing fruit that can help improve mindshare. As the Threadripper series have proven repeatedly, having (extreme) overclockers push the chips to their limit provides an endless stream of performance world record media coverage.

And here’s where the Threadripper 5000 series story gets a little funky.

While AMD has officially abandoned the consumer variants, it hasn’t abandoned Threadripper overclocking. Just one day before recording, AMD officially announced that overclocking would come to the Ryzen Threadripper Pro WX product line.

Now, it’s great that AMD is still looking to enable overclocking support, but, unfortunately, I think they didn’t plan it all that well. What you need to know about motherboard companies is that the consumer team is usually different from the workstation team. And while the consumer teams are typically happy to accommodate overclocking features (even if it’s a low-volume show-case), the workstation teams are typically not. In fact, when AMD presented the opportunity to enable overclocking for Threadripper Pro and WRX8, some motherboard vendors outright refused to develop solutions.

As you’ll see throughout this article, overclocking Ryzen Threadripper 5000 processors requires more than just access to BIOS settings. You need excellent cooling and a great power delivery solution. Enabling this type of powerful platform requires dedicated effort from teams and people who know what it’s like to design over-spec’d motherboards. That knowledge, capability, and experience exist within the consumer teams. That isn’t to say the workstation teams don’t build solid and reliable motherboards; it’s just to say that designing for reliability and stability beyond the stock configuration requires a different approach and mindset.

Anyway, let’s get back to the CPU I’m overclocking in this blog post.

This Ryzen Threadripper 5990X Engineering Sample sports 64 cores and 128 threads featuring the Zen 3 core architecture. It has a base frequency of 2.5 GHz and boosts up to 4.45 GHz. The TDP is 280W.

In this article, we will cover five different overclocking strategies:

  • First, we enable Precision Boost Overdrive 2 and enable DOCP.
  • Second, we tune the Precision Boost Overdrive 2 parameters with Curve Optimizer
  • Third, we will manually tune the Precision Boost Overdrive 2 electrical and thermal parameters to their limits
  • Fourth, we push the PBO 2 parameters to their limits
  • Lastly, we go for a couple of manual overclocks
Zen 3 ryzen threadripper 5990X overclocking strategies

However, before we jump into overclocking, let us quickly review the hardware and benchmarks we use in this article.

AMD Ryzen Threadripper “5990X”: Hardware Overview

Along with the AMD Ryzen Threadripper 5990X ES processor and ASUS ROG Zenith II Extreme Alpha motherboard, in this guide, we will be using two pairs of 16GB G.SKILL Trident Z DDR4-4266 memory sticks, a 120GB Kingston KC400 SSDNow SSD, an Enermax MAXREVO 1500W power supply, the ElmorLabs Easy Fan Controller, the ElmorLabs Power Measurement Device, ElmorLabs EVC2, an EK-Quantum Momentum water block, and EK-Quantum water cooling. All this is mounted on top of our favorite Open Benchtable V2. 

The cost of the components should be around $8,933.

  • AMD Ryzen Threadripper 5990X processor: $5,990?
  • ASUS ROG Zenith II Extreme Alpha: $850
  • EK-Quantum Momentum ROG Zenith II Extreme: $100
  • EK-Quantum Power Kit P360: $578
  • EK-Furious Meltemi 120: $128
  • EK-Quantum Surface P480M: $150
  • 2x G.SKILL Trident Z DDR4-4266 memory: $340
  • Kingston 512B SSDNow SSD: $80
  • Enermax MAXREVO 1500W power supply: $370
  • MSI GT 710: $50
  • ElmorLabs Easy Fan Controller: $20
  • ElmorLabs EVC 2: $32
  • ElmorLabs Power Measurement Device: $45
  • Open Benchtable V2: $200
Zen 3 ryzen threadripper 5990X system cost

Regular viewers will note that the hardware selection is similar to that from SkatterBencher #36, where we overclocked the Ryzen Threadripper 3990X. In that overclocking guide, we identified some critical challenges with overclocking this kind of 64-core beast. The hardware selection in this guide addresses all of the challenges of the 3990X and some new ones

Challenge 1: Input Power

As was the case with the 3990X, and as you’ll find out in this overclocking guide, the Ryzen Threadripper 5990X draws a lot of power and current at full blast. Therefore, I also stick with the Enermax MaxRevo 1500W power supply, which I used with the 3990X. The MaxRevo offers up to 30A on 4 of the 12V rails and up to 125A for all 12V rails combined.

This was sufficient to power the Ryzen Threadripper 3990X as well as this Ryzen Threadripper 5990X ES fully overclocked, which hit over 1200W under load.

Challenge 2: CPU Temperature

Obviously, the CPU temperature will be challenging, as that’s a recurring challenge in most of my overclocking guides. Contrary to the 3990X system, I will not use EK’s flagship Magnitude sTRX4 water block. Instead, I will use EK’s Quantum Momentum monoblock for the Zenith II Extreme motherboard.

The CPU cooling engine is based on the previous generation Velocity sTR4, which was tuned for the multi-chiplet CPU designs. While I don’t expect the CPU cooling performance to be as good as the Magnitude, it should still be sufficient to squeeze more performance out of this CPU.

Challenge 3: VRM Temperature

A challenge that I didn’t explicitly highlight with the 3990X and the Zenith II Extreme is the VRM temperature. However, as you’ll find out in this overclocking guide, this Zen 3 Ryzen Threadripper is pushing the VRM of the Zenith II Extreme Alpha to its absolute limit. Without the help of active liquid cooling, we’d have serious overheating issues.

In fact, I think it’s about time that CPU and motherboard makers start to think about liquid cooling-first designs to maximize the performance of single-socket architectures. Of course, there are already many liquid-cooled motherboards on the market. Still, more often than not, these designs prioritize aesthetics over performance or cost. CPUs like the Ryzen Threadripper pack tremendous performance that can only reliably be unleashed with liquid cooling.

Challenge 4: Water Temperature

As I highlighted in my 3990X overclocking guide, the water temperature was a crucial limiting factor. As in all my overclocking guides, I use the ElmorLabs Easy Fan Controller to control the radiator fans and regulate the water temperature.

Without going into too many details, I have attached an external temperature sensor from the water in the loop to the EFC. Then, I use the low/high setting to map the fan curve from 25 to 40 degrees water temperature. That means the curve initiates the fan at 25 degrees Celsius and ramps up gradually to 100% fan speed at a water temperature of 40 degrees Celsius.

elmorlabs fan curve

With regular desktop CPUs, the CPU temperature reaches TjMax well before my fans run at 100% due to the water temperature. However, with the Ryzen Threadripper 3990X under a sustained multi-threaded workload with PBO enabled, the water temperature exceeds 40 degrees Celsius. That means even though my fans are spinning full blast at 40 degrees, they’re not able to cool down the radiator and water sufficiently. In other words: I am limited by my cooling solution.

As I promised, I upgraded the cooling solution for the Ryzen Threadripper 5000 series processor. In addition to my usual EK-CoolStream PE 360 radiator with 3x EK-Vardar EVO 120ER fans, I added an EK-Quantum Surface P480M with 4x EK-Furious Meltemi 120 fans.

This cooling solution worked perfectly as the highest water temperature I spotted during testing was 37 degrees Celsius, below the maximum temperature of 40 degrees Celsius. However, the fan noise at near-full speed is unbearable, so I wouldn’t recommend this for your daily system.

AMD Ryzen Threadripper “5990X”: Benchmark Overview

We use Windows 11 Enterprise and the following benchmark applications to measure performance and ensure system stability.

Zen 3 ryzen threadripper 5990X benchmarks

Regular viewers will know this is identical to the software we used in SkatterBencher #36 with the Ryzen Threadripper 3990X. I suggest you check out that article to understand some of the challenges related to benchmarking the 64-core Ryzen Threadripper processors.

AMD Ryzen Threadripper “5990X”: Stock Performance

Before we start any overclocking, we must first check the system performance at default settings. A couple of sidenotes, though:

  1. Since this is an engineering sample of an unreleased processor, you should take the stock performance with a grain of salt. The final specifications and performance may have differed significantly from what I obtained. I use the stock benchmark results as a baseline to measure performance increase after overclocking.
  2. The ROG Zenith II Extreme Alpha motherboard enables Precision Boost Overdrive by default.

So, to check the performance at default settings, you must enter the BIOS and

  • Go to the Ai Tweaker menu
  • Enter the Precision Boost Overdrive submenu
  • Set Precision Boost Overdrive to Disabled

Then save and exit the BIOS.

Here is the benchmark performance at stock:

  • Geekbench 5 (single): 1,534 points
  • Geekbench 5 (multi): 23,591 points
  • Cinebench R23 Single: 1,479 points
  • Cinebench R23 Multi: 63,300 points
  • CPU-Z V17.01.64 Single: 621.8 points
  • CPU-Z V17.01.64 Multi: 37,264.8 points
  • V-Ray 5: 43,254 points
  • AI Benchmark: 4,227 points
  • Y-Cruncher PI MT 5B: 227.371 seconds
  • Blender Classroom: 256.19 samples per second
Zen 3 ryzen threadripper 5990X stock benchmark performance

Here is the 3DMark CPU Profile benchmark performance at stock:

  • CPU Profile 1 Thread: 884
  • CPU Profile 2 Threads: 1,744
  • CPU Profile 4 Threads: 3,380
  • CPU Profile 8 Threads: 6,184
  • CPU Profile 16 Threads: 10,632
  • CPU Profile Max Threads: 18,235
Zen 3 ryzen threadripper 5990X stock cpu profile performance

When running Prime 95 Small FFTs with AVX enabled, the average CPU effective clock is 2276 MHz with 0.73 volts. The average CPU temperature is 45.8 degrees Celsius, the average VRM temperature is 31.9 degrees Celsius, and the average water temperature is 27.0 degrees Celsius. The average CPU package power is 218.0 watts.

Zen 3 ryzen threadripper 5990X stock prime 95 avx enabled

When running Prime 95 Small FFTs with AVX disabled, the average CPU effective clock is 2420 MHz with 0.76 volts. The average CPU temperature is 46.2 degrees Celsius, the average VRM temperature is 31.9 degrees Celsius, and the average water temperature is 27.1 degrees Celsius. The average CPU package power is 224.9 watts.

Zen 3 ryzen threadripper 5990X stock prime 95 avx disabled

Going forward, I will simplify the Prime95 result overview to highlight the differences rather than explicitly state the figures.

Like in SkatterBencher #36 with the Threadripper 3990X, Windows and our benchmark applications may not handle over 128 threads very well. So, from the performance tuning perspective, it makes sense to check if turning off SMT helps improve performance with some benchmarks.

AMD Ryzen Threadripper “5990X”: Stock Performance (SMT OFF)

To run stock with SMT disabled, you have to first go into the BIOS

  • Go to the Ai Tweaker menu
  • Enter the Precision Boost Overdrive submenu
    • Set Precision Boost Overdrive to Disabled
  • Go to the Advanced menu
  • Enter the CPU Configuration submenu
    • Set SMT Mode to Disabled

Then save and exit the BIOS.

We re-ran the benchmarks and checked the performance increase compared to the default operation.

  • Geekbench 5 (single): +1.37%
  • Geekbench 5 (multi): +21.36%
  • Cinebench R23 Single: -0.27%
  • Cinebench R23 Multi: -0.10%
  • CPU-Z V17.01.64 Single: -0.14%
  • CPU-Z V17.01.64 Multi: -9.95%
  • V-Ray 5: +15.71%
  • AI Benchmark: +7.41%
  • Y-Cruncher PI MT 5B: +24.92%
  • Blender Classroom: -7.60%
Zen 3 ryzen threadripper 5990X stock benchmark performance smt off

Here is the 3DMark CPU Profile benchmark performance:

  • CPU Profile 1 Thread: +0.34%
  • CPU Profile 2 Threads: +1.38%
  • CPU Profile 4 Threads: +3.28%
  • CPU Profile 8 Threads: +6.02%
  • CPU Profile 16 Threads: +13.76%
  • CPU Profile Max Threads: +14.78%
Zen 3 ryzen threadripper 5990X stock cpu profile performance smt off

Similar to the Ryzen Threadripper 3990X we tested before, some benchmark applications perform better when we disable SMT. Most notably, we see a +25% performance uplift in Y-Cruncher PI and a +21% uplift in Geekbench 5. However, in some benchmarks, we see a performance downgrade. For example, our Blender Classroom performance is down 8%.

  • AVX: +222 MHz
  • NO AVX: +315 MHz

When comparing the Prime95 results, we find that disabling SMT for both AVX and non-AVX workload scenarios provides additional performance headroom. The Precision Boost algorithm boosts the frequency 222 MHz higher in an AVX and 315 MHz higher in a non-AVX all-core multi-threaded workload. This is because disabling SMT allows for additional voltage headroom within the Precision Boost limits. This extra voltage headroom then translates into higher clock frequencies.

Zen 3 ryzen threadripper 5990X stock prime95 results

Important to note is that both the TDC and EDC parameters are at their limit of 215 and 300 amps, respectively. These limits are conservative as the maximum PPT remains well below the TDP limit of 280 watts. In other words, the limitation of this system is not the CPU TDP, but the AMD configured VRM limitations.

Zen 3 ryzen threadripper 5990X stock prime95 details

Of course, we can override these limitations using Precision Boost Overdrive. That’s what we’ll do in our first overclocking strategy.

OC Strategy #1: PBO + D.O.C.P.

In our first overclocking strategy, we simply take advantage of enabling Precision Boost Overdrive 2 and ASUS DOCP.

Precision Boost Overdrive 2

With the launch of Zen 3, AMD introduced an improved version of the Precision Boost Overdrive toolkit, allowing for manual tuning of the parameters affecting the Precision Boost frequency boost algorithm.

Precision Boost Overdrive 2 builds on the PBO implementation of Zen 2. In addition to the overclocking knobs from Zen+ (PPT, TDC, EDC) and Zen 2 (Boost Override and Scalar), Precision Boost Overdrive 2 introduces Curve Optimizer.

precision boost overdrive 2

There are essentially 3 levels of Precision Boost Overdrive

  1. AMD’s stock values, which can be set by disabling PBO
  2. The motherboard vendor values, which are programmed into the BIOS to match the motherboard VRM specification and can be set by enabling PBO
  3. Custom values, which can be programmed by the end-user

I explored the ins and outs of Precision Boost Overdrive 2 tuning in my Ryzen 7 5700G SkatterBencher article. If you want to learn more about the impact of each of these settings, I suggest you check out that article.

In this overclocking strategy, we’re just enabling Precision Boost Overdrive, whereas, in the following strategies, we’ll explore tuning the parameters.

By enabling Precision Boost Overdrive, we rely on the motherboard pre-programmed PBO parameters.

Zen 3 ryzen threadripper 5990X pbo enabled settings

We find that the following values have changed:

  • PPT limit from 280W to 600W
  • TDC limit from 215A to 400A
  • EDC limit from 300A to 470A
  • FIT limit from 2024 to 14171

Increasing the PPT and especially the TDC and EDC limit will help unleash the frequency in multi-threaded workloads previously limited by the EDC. The CPU FIT limit increases by changing the Scalar and encourages the CPU to pursue higher voltages. The Frequency limit can technically also increase using a +200MHz boost override, but this is not done with this particular BIOS. The THM (temperature) and VID (voltage) limits are hardcoded and cannot be manually increased.

DOCP – Direct Over Clock Profile

DOCP stands for Direct Over Clock Profile. It is an ASUS technology that aims to replicate the Intel XMP feature we know from Intel platforms. XMP allows memory vendors such as G.SKILL to program higher performance settings onto the memory sticks. If the motherboard supports XMP, you can enable higher performance with a single BIOS setting. So, it saves you lots of manual configuration.

While our memory kit is rated at DDR4-4266, I will run it at DDR4-3600 with the fabric clock in sync at 1800 MHz as it wasn’t easy to get higher frequencies to boot.

Upon entering the BIOS

  • Go to the Ai Tweaker menu
  • Set Ai Overclock Tuner to DOCP. Standard
  • Set Memory Frequency to DDR4-3600MHz
  • Set FCLK Frequency to 1800MHz
  • Enter the Precision Boost Overdrive submenu
    • Set Precision Boost Overdrive to Enabled

Then save and exit the BIOS.

We re-ran the benchmarks and checked the performance increase compared to the default operation with both SMT enabled and disabled.

SMT Enabled

  • Geekbench 5 (single): +1.76%
  • Geekbench 5 (multi): +18.79%
  • Cinebench R23 Single: -0.81%
  • Cinebench R23 Multi: +38.82%
  • CPU-Z V17.01.64 Single: +0.11%
  • CPU-Z V17.01.64 Multi: +29.19%
  • V-Ray 5: +6.22%
  • AI Benchmark: +20.60%
  • Y-Cruncher PI MT 5B: +10.65%
  • Blender Classroom: +36.24%
Zen 3 ryzen threadripper 5990X pbo enabled benchmark performance

Here is the 3DMark CPU Profile benchmark performance:

  • CPU Profile 1 Thread: +0.34%
  • CPU Profile 2 Threads: +1.38%
  • CPU Profile 4 Threads: +3.58%
  • CPU Profile 8 Threads: +7.20%
  • CPU Profile 16 Threads: +16.47%
  • CPU Profile Max Threads: +29.92%
Zen 3 ryzen threadripper 5990X pbo enabled cpu profile performance

SMT Disabled

  • Geekbench 5 (single): +3.19%
  • Geekbench 5 (multi): +37.86%
  • Cinebench R23 Single: -0.95%
  • Cinebench R23 Multi: +18.14%
  • CPU-Z V17.01.64 Single: -0.13%
  • CPU-Z V17.01.64 Multi: +1.09%
  • V-Ray 5: +39.26%
  • AI Benchmark: +39.12%
  • Y-Cruncher PI MT 5B: +38.58%
  • Blender Classroom: +11.10%
Zen 3 ryzen threadripper 5990X pbo enabled benchmark performance smt off

Here is the 3DMark CPU Profile benchmark performance:

  • CPU Profile 1 Thread: +0.34%
  • CPU Profile 2 Threads: +1.49%
  • CPU Profile 4 Threads: +3.73%
  • CPU Profile 8 Threads: +7.70%
  • CPU Profile 16 Threads: +19.32%
  • CPU Profile Max Threads: +44.26%
Zen 3 ryzen threadripper 5990X pbo enabled cpu profile performance smt off

We get significant performance gains in all multi-threaded benchmark applications by simply enabling Precision Boost Overdrive. The highest performance increase is in 3DMark CPU Profile Max Threads with +44.26% over stock performance. We also get a slight improvement in tests that use only a few cores, thanks to the increased DRAM and Fabric clock frequency.

  • SMT + AVX: +1078 MHz
  • SMT + NO AVX: +1169 MHz
  • NO SMT + AVX: +1100 MHz
  • NO SMT + NO AVX: +1059 MHz

In Prime 95, simply enabling Precision Boost Overdrive gives us a ridiculous performance improvement across the board. Across all Prime 95 configurations, we get an additional 1 GHz of performance; with SMT enabled and AVX disabled, we almost get 1.2GHz higher frequency. That’s insane! If you remember, the performance uplift from enabling PBO on the 3990X was “only” about 700 MHz.

Zen 3 ryzen threadripper 5990X pbo enabled prime95 results

Another thing to note is that while the CPU temperature increased to about 70 degrees Celsius, the limiting factor is neither the CPU, the VRM, nor the water temperature. However, as in our stock configuration, we are limited by the PBO VRM configuration. Specifically, we reached the maximum allowed EDC of 470 amps in every one of our tests.

Zen 3 ryzen threadripper 5990X pbo enabled prime95 details

OC Strategy #2: PBO Curve Optimized + D.O.C.P.

In our second overclocking strategy, we will use Precision Boost Overdrive 2’s novel tuning tool, Curve Optimizer.

Precision Boost Overdrive 2: Curve Optimizer

As I mentioned, Curve Optimizer is a key new feature of Precision Boost Overdrive 2.

Curve Optimizer allows end-users to adjust the voltage-frequency curve for each CPU core separately. You can offset the entire curve by up to 30 steps in either a positive or negative direction. Each step represents between 3 and 5 mV. So, quick math tells us we can increase or decrease the curve by up to 150 mV.

precision boost overdrive 2 curve optimizer

When you adjust the voltage-frequency curve with a negative point offset, two things happen.

  1. First, you effectively tell the CPU that for a given frequency, it needs less voltage. And, as a consequence, at a given voltage, it can apply a higher frequency. So, when the Precision Boost 2 algorithm determines sufficient power and temperature headroom to use 1.35V, with the negative point offset, it will target a higher frequency.
  2. Second, the CPU temperature will be lower because you use less voltage at a given frequency. That extra thermal headroom will also encourage the Precision Boost algorithm to target higher voltages and frequencies.

I explored the ins and outs of Curve Optimizing with Precision Boost Overdrive 2 in my Ryzen 7 5700G SkatterBencher blog post. If you want to learn more about the impact of Curve Optimizer, I suggest you check out that blog post.

As I mentioned already, Curve Optimizer is available on a per-core basis. At least, in theory. While I was hoping to spend a couple of nights curve optimizing every single of the 64 available CPU cores, unfortunately, with this beta BIOS, I can only set Curve Optimizer for all cores. The Per Core option is available, but the options to adjust each core are missing. I did try flashing the board with the latest public BIOS, but then the system no longer booted up.

For this overclocking strategy, I use a curve optimizer setting of -15. While up to -30 worked in most benchmarks, it didn’t pass Prime95 stability testing.

In addition to Curve Optimizer, compared to the previous overclocking strategy, I also changed the Fmax Override from 0 MHz to 200 MHz and the Scalar from 7X to 10X.

Fmax Override, also called Max CPU Boost Clock Override, simply increases the arbitrary clock frequency ceiling. On AMD Ryzen CPUs, you can raise the ceiling up to 200 MHz in steps of 25 MHz.

Scalar is a tool that allows users to increase the FIT limit. FIT stands for Failures in Time and is a standard reliability metric in the semiconductor industry. One FIT is defined as one failure every billion hours of operation. Every CPU has a specified FIT value from the factory, and the Scalar allows you to manually increase this value. On this particular CPU, the standard FIT is 2024; when applying the 10X Scalar, the FIT becomes 20244.

The Precision Boost algorithm will consider the FIT limit to evaluate the voltage headroom. With a higher allowed FIT, the CPU will allow for higher voltages to be used despite potentially harming the lifespan of the CPU.

Zen 3 ryzen threadripper 5990X pbo curve optimized settings

Upon entering the BIOS

  • Go to the Ai Tweaker menu
  • Set Ai Overclock Tuner to DOCP. Standard
  • Set Memory Frequency to DDR4-3600MHz
  • Set FCLK Frequency to 1800MHz
  • Enter the Precision Boost Overdrive submenu
    • Set Precision Boost Overdrive to Enabled
  • Go to the Advanced menu
  • Enter the AMD Overclocking submenu
    • Click Accept
    • Enter the Precision Boost Overdrive submenu
      • Set Precision Boost Overdrive to Advanced
      • Set Precision Boost Overdrive Scalar to Manual
      • Set Precision Boost Overdrive Scalar to 10X
      • Enter the Curve Optimizer submenu
        • Set Curve Optimizer to All Cores
        • Set All Core Curve Optimizer Sign to Negative
        • Set All Core Curve Optimizer Magnitude to 15
      • Leave the Curve Optimizer submenu
      • Set Max CPU Boost Clock Override to 200MHz

Then save and exit the BIOS.

We re-ran the benchmarks and checked the performance increase compared to the default operation with both SMT enabled and disabled.

SMT Enabled

  • Geekbench 5 (single): +8.02%
  • Geekbench 5 (multi): +19.44%
  • Cinebench R23 Single: +3.65%
  • Cinebench R23 Multi: +42.97%
  • CPU-Z V17.01.64 Single: +3.78%
  • CPU-Z V17.01.64 Multi: +29.89%
  • V-Ray 5: +8.51%
  • AI Benchmark: +22.21%
  • Y-Cruncher PI MT 5B: +10.88%
  • Blender Classroom: +45.31%
Zen 3 ryzen threadripper 5990X pbo curve optimized benchmark performance smt off

Here is the 3DMark CPU Profile benchmark performance:

  • CPU Profile 1 Thread: +4.30%
  • CPU Profile 2 Threads: +5.39%
  • CPU Profile 4 Threads: +8.05%
  • CPU Profile 8 Threads: +8.60%
  • CPU Profile 16 Threads: +20.54%
  • CPU Profile Max Threads: +34.81%
Zen 3 ryzen threadripper 5990X pbo curve optimized cpu profile performance

SMT Disabled

  • Geekbench 5 (single): +8.02%
  • Geekbench 5 (multi): +38.69%
  • Cinebench R23 Single: +3.38%
  • Cinebench R23 Multi: +20.03%
  • CPU-Z V17.01.64 Single: +3.04%
  • CPU-Z V17.01.64 Multi: +4.59%
  • V-Ray 5: +42.19%
  • AI Benchmark: +39.16%
  • Y-Cruncher PI MT 5B: +38.88%
  • Blender Classroom: +12.92%
Zen 3 ryzen threadripper 5990X pbo curve optimized benchmark performance smt off

Here is the 3DMark CPU Profile benchmark performance:

  • CPU Profile 1 Thread: +4.75%
  • CPU Profile 2 Threads: +5.69%
  • CPU Profile 4 Threads: +8.28%
  • CPU Profile 8 Threads: +12.35%
  • CPU Profile 16 Threads: +23.90%
  • CPU Profile Max Threads: +45.92%
Zen 3 ryzen threadripper 5990X pbo curve optimized cpu profile performance smt off

Combining the increased Fmax and using Curve Optimizer should impact the fewer-threaded applications more than the multi-threaded applications. We see improvements in those benchmarks by up to 8% in, for example, Geekbench 5 Single. In multi-threaded applications, we also marginally improve our performance up to +45.92% in 3DMark CPU Profile Max Threads.

  • SMT + AVX: +140 MHz
  • SMT + NO AVX: +83 MHz
  • NO SMT + AVX: +94 MHz
  • NO SMT + NO AVX: +78 MHz

Using Curve Optimizer allows the CPU to use less voltage for a given frequency and thus potentially boost to higher frequencies with a given voltage. We see an improvement of about 100 MHz in Prime 95 stable frequencies with similar or slightly lower effective voltage.

Zen 3 ryzen threadripper 5990X pbo curve optimized prime 95 results
Zen 3 ryzen threadripper 5990X pbo curve optimized prime 95 details

OC Strategy #3: PBO Tuned (PPT, TDC, EDC) + D.O.C.P.

In our third overclocking strategy, we will manually tune the Precision Boost Overdrive 2 electrical and thermal parameters to their limits

Precision Boost Overdrive 2: PPT, TDC, & EDC

As I explained earlier in this article, Zen 3 processors like the Ryzen Threadripper 5000 series come with the Precision Boost Overdrive 2 overclocking toolkit. This toolkit includes a variety of settings that can be used to manually finetune the behavior of the Precision Boost algorithm.

We used several manual tools to get higher frequencies in the previous overclocking strategies. However, we relied on values pre-programmed in the BIOS to work around some power and electrical limitations.

However, looking at the Prime 95 results from OC Strategies 2 and 3, we find that our system is still hitting limits. In all test scenarios, we hit the EDC limit of 470 amps and got very close to the TDC limit of 400 amps.

Prime95 is not the only application we find our CPU hitting the ceiling. When we monitor the behavior in each of the benchmarks, we hit the EDC limit in Geekbench 5, Cinebench R23, CPU-Z, Y-Cruncher, and Blender.

Zen 3 ryzen threadripper 5990X pbo enabled benchmark limits

We can get around these limits by manually tuning Precision Boost Overdrive 2. Simply go into the BIOS and gradually increase the limits until you find your benchmark applications no longer being bottlenecked by any of the parameters.

With regular Ryzen CPUs, you’ll find that eventually, the limiting factor for the CPU becomes either the maximum Precision Boost frequency limit or the CPU temperature.

However, the 64 core Ryzen Threadripper 5990X is a whole different beast. The combination of low-power, high-voltage for single-threaded applications and high-power, low-voltage for multi-threaded applications is extremely tough on the VRM. Ultimately, we find ourselves in a situation where transient currents are the limiting factor.

Practically, we have to limit the EDC to 800A. If we don’t, the VRM will shut down when running Y-Cruncher, AI Benchmark, or initializing Prime 95.

So, after tuning, I use the following PBO settings:

Zen 3 ryzen threadripper 5990X pbo tuned settings

Upon entering the BIOS

  • Go to the Ai Tweaker menu
  • Set Ai Overclock Tuner to DOCP. Standard
  • Set Memory Frequency to DDR4-3600MHz
  • Set FCLK Frequency to 1800MHz
  • Enter the Precision Boost Overdrive submenu
    • Set Precision Boost Overdrive to Manual
    • Set PPT Limit to 1000
    • Set TDC Limit to 800
    • Set EDC Limit to 800
    • Set Precision Boost Overdrive Scalar to Manual
    • Set Precision Boost Overdrive Scalar to 10X
    • Set Max CPU Boost Clock Override to 200MHz
  • Go to the Advanced menu
  • Enter the AMD Overclocking submenu
    • Click Accept
    • Enter the Precision Boost Overdrive submenu
      • Set Precision Boost Overdrive to Advanced
      • Set Precision Boost Overdrive Scalar to Manual
      • Set Precision Boost Overdrive Scalar to 10X
      • Enter the Curve Optimizer submenu
        • Set Curve Optimizer to All Cores
        • Set All Core Curve Optimizer Sign to Negative
        • Set All Core Curve Optimizer Magnitude to 15
      • Leave the Curve Optimizer submenu
      • Set Max CPU Boost Clock Override to 200MHz

Then save and exit the BIOS.

We re-ran the benchmarks and checked the performance increase compared to the default operation.

SMT Enabled

  • Geekbench 5 (single): +8.28%
  • Geekbench 5 (multi): +22.08%
  • Cinebench R23 Single: +3.72%
  • Cinebench R23 Multi: +43.77%
  • CPU-Z V17.01.64 Single: +3.84%
  • CPU-Z V17.01.64 Multi: +31.75%
  • V-Ray 5: +8.78%
  • AI Benchmark: +26.28%
  • Y-Cruncher PI MT 5B: +11.29%
  • Blender Classroom: +48.21%
Zen 3 ryzen threadripper 5990X pbo tuned benchmark performance smt off

Here is the 3DMark CPU Profile benchmark performance:

  • CPU Profile 1 Thread: +4.41%
  • CPU Profile 2 Threads: +5.50%
  • CPU Profile 4 Threads: +9.02%
  • CPU Profile 8 Threads: +8.64%
  • CPU Profile 16 Threads: +20.60%
  • CPU Profile Max Threads: +44.98%
Zen 3 ryzen threadripper 5990X pbo tuned cpu profile performance

SMT Disabled

  • Geekbench 5 (single): +8.34%
  • Geekbench 5 (multi): +42.75%
  • Cinebench R23 Single: +3.92%
  • Cinebench R23 Multi: +22.58%
  • CPU-Z V17.01.64 Single: +4.08%
  • CPU-Z V17.01.64 Multi: +5.31%
  • V-Ray 5: +43.79%
  • AI Benchmark: +46.18%
  • Y-Cruncher PI MT 5B: +40.07%
  • Blender Classroom: +13.28%
Zen 3 ryzen threadripper 5990X pbo tuned benchmark performance smt off

Here is the 3DMark CPU Profile benchmark performance:

  • CPU Profile 1 Thread: +4.75%
  • CPU Profile 2 Threads: +5.96%
  • CPU Profile 4 Threads: +9.17%
  • CPU Profile 8 Threads: +12.42%
  • CPU Profile 16 Threads: +23.72%
  • CPU Profile Max Threads: +61.86%
Zen 3 ryzen threadripper 5990X pbo tuned cpu profile performance smt off

After manually tuning the PBO PPT, TDC, and EDC parameters, we see a performance uplift in most of the multi-threaded benchmark applications. Surprisingly, we find the most significant performance increase in 3DMark CPU Profile, which improves 16 percentage points and is now +61.86% higher than stock.

  • SMT + AVX: +337 MHz
  • SMT + NO AVX: +243 MHz
  • NO SMT + AVX: +217 MHz
  • NO SMT + NO AVX: +131 MHz

In Prime 95, find that tuning the PPT, TDC, and EDC provides additional sustained all-core frequency across the board. The most significant frequency is in the test scenario with SMT and AVX enabled, as we get an extra 337 MHz. Also noteworthy is that we achieve a sustained frequency of 4 GHz with 1.033 volts on all 64 cores when disabling SMT and AVX.

Zen 3 ryzen threadripper 5990X pbo tuned prime 95 result

The primary limiting factor for the Prime 95 sustained workload is the CPU temperature, which reached 95 degrees Celsius, and that is the maximum allowed temperature. However, even if we could decrease the CPU temperature, we find that the VRM temperature is already 80 degrees Celsius and nearing its thermal limit.

Furthermore, the water temperature is around 36 degrees Celsius, which is also near the 40 degrees Celsius where our fan curve would be at 100%. We’re already sporting 2 radiators with 7 fans making a severe amount of noise …

And, last but not least, look at those EDC values! When we disable AVX, the EDC is a sustained 800 amps throughout the entirety of the 30-minute Prime 95!

Zen 3 ryzen threadripper 5990X pbo tuned prime 95 details

I don’t think I’ve ever felt so on the limit with what’s probably the most powerful desktop system in the world.

OC Strategy #4: PBO Maxed (PPT, TDC, EDC) + D.O.C.P.

In the fourth overclocking strategy, we push the Precision Boost Overdrive parameters to their limits and see what peak performance would look like if it wasn’t for the VRM limitations.

As we saw in the previous OC Strategy, we must hard limit the EDC parameter to 800 amps to ensure VRM stability across all benchmarks and stability tests. When exceeding the 800A limit, we find that the system will shut down while running Y-Cruncher or AI Benchmark, or when loading up Prime 95 on all 64 cores.

If we check the behavior in specific benchmarks again, we still hit the maximum EDC in Geekbench 5, Cinebench R23, CPU-Z, Y-Cruncher, and Blender.

Zen 3 ryzen threadripper 5990X pbo tuned benchmark limits

What may surprise you is that we also hit the EDC limit when disabling SMT. In fact, in all benchmarks bar 3DMark CPU Profile, we either get close to or hit the EDC limit.

Zen 3 ryzen threadripper 5990X pbo tuned benchmark limits

In this overclocking strategy, we simply push the EDC limit as high as it needs to until it’s no longer a limiting factor for our benchmark applications. That appears to be around 1050 amps – yes … over one kiloamp.

In fact, we see EDC peak over 1000 amps in multiple benchmarks: Geekbench 5, CPU-Z, Y-Cruncher, and Blender.

In addition to increasing the EDC parameter, we set the Curve Optimizer to negative 30 for all cores. Again, while this isn’t Prime 95 stable, it does seem to pass all benchmarks.

Zen 3 ryzen threadripper 5990X pbo maxed settings

Upon entering the BIOS

  • Go to the Ai Tweaker menu
  • Set Ai Overclock Tuner to DOCP. Standard
  • Set Memory Frequency to DDR4-3600MHz
  • Set FCLK Frequency to 1800MHz
  • Enter the Precision Boost Overdrive submenu
    • Set Precision Boost Overdrive to Manual
    • Set PPT Limit to 1000
    • Set TDC Limit to 800
    • Set EDC Limit to 1100
    • Set Precision Boost Overdrive Scalar to Manual
    • Set Precision Boost Overdrive Scalar to 10X
    • Set Max CPU Boost Clock Override to 200MHz
  • Go to the Advanced menu
  • Enter the AMD Overclocking submenu
    • Click Accept
    • Enter the Precision Boost Overdrive submenu
      • Set Precision Boost Overdrive to Advanced
      • Set Precision Boost Overdrive Scalar to Manual
      • Set Precision Boost Overdrive Scalar to 10X
      • Enter the Curve Optimizer submenu
        • Set Curve Optimizer to All Cores
        • Set All Core Curve Optimizer Sign to Negative
        • Set All Core Curve Optimizer Magnitude to 30
      • Leave the Curve Optimizer submenu
      • Set Max CPU Boost Clock Override to 200MHz

Then save and exit the BIOS.

We re-ran the benchmarks and checked the performance increase compared to the default operation.

  • Geekbench 5 (single): +8.41% (SMT OFF)
  • Geekbench 5 (multi): +43.22% (SMT OFF)
  • Cinebench R23 Single: +3.92% (SMT OFF)
  • Cinebench R23 Multi: +50.27% (SMT ON)
  • CPU-Z V17.01.64 Single: +4.15% (SMT OFF)
  • CPU-Z V17.01.64 Multi: +32.70% (SMT ON)
  • V-Ray 5: +46.16% (SMT OFF)
  • AI Benchmark: +47.65% (SMT OFF)
  • Y-Cruncher PI MT 5B: +40.13% (SMT OFF)
  • Blender Classroom: +48.21% (SMT ON)
Zen 3 ryzen threadripper 5990X pbo maxed cpu benchmark performance

Here is the 3DMark CPU Profile benchmark performance

Zen 3 ryzen threadripper 5990X pbo maxed cpu profile performance

OC Strategy #5: Manual Overclocking

In our fifth and final overclocking strategy, I will try manual overclocking. However, unlike with the Ryzen Threadripper 3990X, I won’t cover multiple Prime95 stable scenarios but will focus on optimizing the performance of specific benchmark applications: AI Benchmark, Cinebench R23 and 3DMark CPU Profile.

One could question the use-case for manual overclocking the Ryzen Threadripper CPUs. Just like with all Ryzen processors, the major downside of manual overclocking is that you lose the benefits of Precision Boost technology in low-threaded benchmark applications. So, whereas this 5990X can boost up to 4650 MHz with Precision Boost, when manual overclocking, it will be limited to your highest manual frequency.

However, I believe there’s a good use case for manual overclocking on Ryzen Threadripper.

The main advantage of Precision Boost is that it changes the voltage and frequency dynamically depending on the workload. The main disadvantage is that the constant change in voltage is pretty tough on the VRM. As we learned from our previous overclocking strategies, this may even result in system instability when running specific applications.

When manual overclocking, you avoid the stress on the VRM from the constant voltage changes. Furthermore, you also limit the maximum voltage to a much lower value than Precision Boost. Overall, for Ryzen Threadripper, manual overclocking should be more optimal for the VRM.

In addition to the less stress on the VRM, manual tuning has even more benefits.

First, automatic overclocking and frequency boosting technologies always leave a little margin on the table. We can exploit this margin and finetune for application stability when manual overclocking with our specific hardware configuration.

Second, in multi-threaded applications, Precision Boost Overdrive applies a single frequency to every core. However, on AMD Ryzen CPUs, you can set the frequency for each CCX separately. So, we can exploit the fact that some CCXs may overclock better than others.

ryzen threadripper manual overclocking advantage

To better understand the performance tuning opportunities embedded in the Ryzen Threadripper 5990X processor, let’s look at its architecture in more detail.

CPU Core Frequency & Voltage

The Ryzen Threadripper 5990X would’ve been AMD’s Chagall Zen 3-based flagship CPU. Chagall is derived from the EPYC Milan server product line and features no less than nine chips on package: eight (8) CCDs and a single IO die.

ryzen threadripper 5000 cpu

CCD stands for Core Chiplet Die and is just a die on a Ryzen CPU with CPU cores. The Zen cores are packed together in a CCX, or Core Complex. A Zen 3 CCX consists of up to eight individual cores, each with their L1 and L2 cache and a shared 32MB of L3 cache.

zen 3 ccx layout

The frequency of the CPU cores is driven by a 100 MHz reference clock input. Each CCX has its own PLL and thus can run an independent frequency. The cores within a CCX share the same PLL, so they’ll run at the same frequency. That means, for the Ryzen Threadripper 5990X, we can set an independent frequency for each of the 8 CCXs.

ryzen threadripper 5000 cpu frequency

Ironically, that means we have less tuning granularity than with the Zen 2 Ryzen Threadripper 3990X as Zen 2 has 2 CCXs in 1 CCD and thus double the CCX frequency tuning capabilities.

zen 2 zen 3 ccx

The voltage of the CPU cores is provided by the VDDCR_CPU voltage rail. This voltage is shared across all the CCDs, so each CPU core will be provided with the same voltage.

ryzen threadripper cpu core voltage

Choosing the proper manual voltage is always a matter of finding a suitable trade-off between increased overclocking potential, the thermal challenges that come with increased voltage, and of course, consideration of CPU lifespan.

Per-CCX Frequency Tuning Process

With that last thought, we kick off what’s arguably the most tedious or exciting aspect of Ryzen Threadripper overclocking: per-CCX frequency tuning.

Our limiting factor will ultimately be the cooling solution as power consumption increases exponentially with operating voltage and temperature scales (somewhat) linearly with power consumption.

The maximum voltage will be determined by the application we’re tuning for. So, the first step in our tuning process would be to set a fixed CPU ratio and check the maximum temperature when running our workload. If there’s thermal headroom left, increase the operating voltage.

Once we know the maximum voltage, we can tune the CPU ratio of each CCX. Simply increase the CPU ratio of one CCX until the application shows signs of instability, then back off. Do this for each CCX sequentially, and you’ll end up with the maximum stable per-CCX frequency for a given voltage.

We do this for the applications we include in our manual overclocking strategy. In this table, you can find the maximum ratio for each of the CCXs

Zen 3 ryzen threadripper 5990X manual overclock benchmark frequency

Just as a reminder: the values in this table are for my specific system and a specific stability test. Your CPU may have wildly different values depending on the CPU sample, cooling and motherboard, and your chosen stability test.

Memory Frequency & Voltage

The AMD Chagall CPU package is divided into 4 equal quadrants. Each quadrant consists of a pair of CCDs with access to two linked memory channels. So, in total, Chagall processors offer up to eight channels of DDR4 memory, half of which are disabled on the Ryzen Threadripper non-Pro processors. Even though that’s half of what the Zen 3 Ryzen EPYC server processors offer, it’s still double the channels compared to the desktop Zen 3 Ryzen CPUs.

ryzen threadripper quadrants

On Zen 3 processors, there are up to 9 chips on package: 1 I/O die and up to eight CCDs. The CCD contains one CCX with the CPU cores and an infinity fabric connection. All other I/O connectivity, including the memory controllers, is located in the on-package 14nm I/O die. This ensures better overall latency for memory access but puts the onus on a fast Fabric clock to ensure high performance. When a CPU core needs to access data in the system memory, it connects via the infinity fabric to the I/O die and then accesses the memory controller

AMD officially supports up to DDR4-3200, but Ryzen CPUs can push the memory frequency slightly higher than that. That said, it’s not as easy as it may sound.

To make a long story short, there are 3 relevant frequencies when it comes to system memory performance:

  • mClk, or memory clock, is the frequency of your DDR4 memory
  • uClk, or memory controller clock, is the frequency of the integrated memory controllers
  • fClk, or fabric clock, is the frequency of the infinity fabric.
ryzen mclk uclk fclk

The system memory and memory controller frequency are driven by the same 100 MHz reference clock used for the CPU cores.

The memory controller and memory frequency are tied together. You can run both at the same frequency or run the memory controller at half the system memory frequency when memory gear-down mode is enabled.

ryzen threadripper 5000 memory frequency

The voltage of the memory is provided by two VDDIO_MEM_S3 voltage rails. Each voltage rail powers the memory linked to a specific memory controller. The voltage for the memory controller and fabric is provided by the VDDCR_SOC voltage rail.

ryzen threadripper 5000 memory voltage

We continue to use our XMP memory timings for our configuration but change the memory multiplier to maintain synchronous mode. So, we manually set the memory to DDR4-3600.

Infinity Fabric Frequency

When the CPU cores want to store or retrieve data from the system memory, it does this via the Infinity Fabric and the memory controllers in the IOD chip. By default, these three parts are running in sync, meaning they all operate at the same frequency. When overclocking the system memory, you can choose to use it in synchronous or asynchronous mode.

Synchronous mode is relatively taxing for the CPU, so on most Ryzen CPUs, the system will automatically enable “Asynchronous mode” beyond a particular memory frequency.

In asynchronous mode, the memory controller will operate at half the system memory frequency. This will result in a performance penalty. The penalty size is application-specific and depends on the final memory frequency.

As the memory overclocking capabilities of the Chagall processors are relatively limited, not in the least because of the 4 memory controllers, we prefer to run in synchronous mode.

The fabric clock frequency is driven by the same 100 MHz reference clock used for the CPU cores. It can be clocked independently from the CPU cores, memory controller, or memory frequency.

ryzen threadripper 5000 fabric clock

The fabric voltage is provided by the VDDCR_SOC voltage rail, which also powers the memory controllers. While there’s only one incoming voltage rail to the IO die, AMD uses DLDOs to internally create additional voltage rails. You’ll find options like VDDG for the Fabric Phy in the BIOS. VDDG is a DLDO-powered voltage derived from the VDDCR_CPU or VDDCR_SOC voltage rails.

ryzen threadripper 5000 fabric voltage

For the Zen 3 processors, generally, synchronous mode is supported up to DDR4-3600 and 1800 MHz Fabric Clock. However, some people may be able to reach a bit higher. On this particular system, I was able to get an 1867 MHz fabric clock

Now that we know the ins and outs of Ryzen Threadripper 5000 manual overclocking let’s jump into the BIOS. I will provide the BIOS settings of the AI Benchmark manual overclocking scenario where we use all 64 cores in a heavy multi-threaded application with SMT disabled.

Upon entering the BIOS

  • Go to the Ai Tweaker menu
  • Set Ai Overclock Tuner to DOCP. Standard
  • Set Memory Frequency to DDR4-3600MHz
  • Set FCLK Frequency to 1800MHz
  • Enter the CPU Core Ratio (Per CCX) submenu
    • Set Core VID to 1.275
    • Set CCD0 CCX0 to 43.25
    • Set CCD1 CCX0 to 43.00
    • Set CCD2 CCX0 to 41.75
    • Set CCD3 CCX0 to 41.75
    • Set CCD4 CCX0 to 43.75
    • Set CCD5 CCX0 to 42.75
    • Set CCD6 CCX0 to 41.75
    • Set CCD7 CCX0 to 42.25
  • Leave the CPU Core Ratio (Per CCX) submenu
  • Go to the Advanced menu
  • Enter the CPU Configuration submenu
    • Set SMT Mode to Disabled

Then save and exit the BIOS.

We re-ran the benchmarks and checked the performance increase compared to the default operation.

The performance improvements from manual tuning in the three benchmarks range from 1% to 11%. Ultimately, the headroom boils down to the characteristics of the specific workload.

Oh, and yea, that’s 100,000 points in Cinebench R23 with a single socket water-cooled CPU …

Zen 3 ryzen threadripper 5990X manual overclock benchmark performance

In a benchmark like AI Benchmark, which heavily relies on AVX acceleration and has a mix of single-threaded and multi-threaded aspects, you’ll find that the Precision Boost algorithm is pretty good at maximizing the performance. When manual tuning, you can increase the multi-threaded performance but will not match the single-threaded frequency boosts.

In a benchmark like Cinebench R23, a heavy multi-threaded workload, you’ll find that exploiting the margins through manual tuning can yield an additional 5% performance. The main limitation will be your cooling solution, which restricts the maximum voltage and associated stable operating frequency.

In a benchmark like 3DMark CPU Profile, a light multi-threaded workload, you’ll find that a superior cooling solution will provide maximum thermal headroom. This enables much higher operating voltage and thus higher frequency. You can increase the frequency beyond the artificial Precision Boost frequency limit by manual overclocking. Therefore, you can achieve additional performance improvements of over 10%.

AMD Ryzen Threadripper “5990X”: Conclusion

All right, let us wrap this up.

I had the unique opportunity to check out what a consumer version of a Zen 3 Ryzen Threadripper would look like. Since this is an early engineering sample paired with a beta BIOS, I’d take the specific performance results with a grain of salt. However, the overclocking experience should translate pretty well to final silicon.

The first point I want to make, and I don’t think I’m exaggerating when I say this, is undoubtedly the more powerful desktop system I’ve ever seen. When you unleash the power and performance with Precision Boost Overdrive, this CPU pushes everything to the limit: motherboard VRM, liquid cooling solution, the power supply, and obviously, the compute performance. I mean, Holy F-ing Sh*t, you can get 100,000 points in Cinebench R23 with just a regular liquid cooling solution.

Second, while I sympathize with the idea that it’d be great to have the consumer Ryzen Threadripper 5000 CPUs available in the market, I do see there might be a problem. At stock, with PBO disabled, the performance of this 5990X isn’t much better than the 3990X I tested a while back. That’s mainly because the standard Precision Boost parameters aggressively cap the operating frequency, especially in all-core workloads. While enabling PBO unleashes the performance, I worry about existing sTRX4 motherboards on the market not having a sufficiently over-spec’d VRM to power an unleased Threadripper 5000.

In line with that last thought, in my humble opinion, I think we need to look with more care at liquid-cooling-first motherboard designs. While there are several liquid-cooled motherboards on the market already, they typically prioritize aesthetics over performance or cost. To fully unleash the full potential of powerful CPUs like the Ryzen Threadripper, however, you need over-spec’d VRMs designed for liquid cooling.

Anyway, that’s all for today!

If the Ryzen Threadripper Pro 5000 CPUs become overclockable, I might have a look at that sometime in the future. If not, the next time I’ll look at an AMD Ryzen CPU is probably in August.

I’d like to thank my Patreon supporters for supporting my work.

As usual, if you have any questions or comments, feel free to drop them in the comment section below. 

See you next time!

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