Arrow Lake D2D Overclocking

arrow lake d2d overclocking skatterbencher

We have a closer look at tuning the performance of the the Arrow Lake D2D, or die-to-die, located between the various Tiles.

Arrow Lake is Intel’s revolutionary new processor for mainstream desktop, featuring new P-cores and E-cores, disaggregated tile-based 3D Foveros packaging, an integrated NPU for AI acceleration, a next-generation uncore, DLVR power rails, and so much more.

arrow lake intel core ultra 200s

In this blog post series, I have a closer look at Arrow Lake and explore its performance tuning and overclocking opportunities. I will cover the Compute (P-core, E-core, Graphics, NPU), Memory Subsystem (DDR, MC), and Data Fabric (Ring, NGU, D2D).

Arrow Lake D2D: Introduction

D2D stands for Die-to-Die. It is the interface between the various tiles on the Arrow Lake package. There are three/four D2D links connecting the various tiles on the Arrow Lake package:

  1. SOC-Compute (H-IDI protocol) – P-core, E-core, Ring
  2. SOC-Graphics (CXL protocol) – Integrated Graphics
  3. SOC-IOE (PSF protocol) – IO extension
  4. SOC-ADM (CMI protocol) – Adamantine

On Arrow Lake, only the SOC-Compute D2D can be overclocked. The base frequency is 2.1 GHz.

meteor lake i/o data fabric

Arrow Lake D2D: Clocking

The clocking of the D2D is similar to other parts on the CPU: a reference clock is multiplied with a ratio to achieve the eventual operating frequency.

arrow lake clocking topology

Reference Clock

The 100 MHz reference clock frequency is generated internally by the SoC PLL. However, it can also be clocked with an external clock generator providing the reference clock for the SoC PLL. This clock affects nearly all the IP blocks of Arrow Lake, except for those in the Compute Tile and the PCIe/DMI links. You can configure the SOC BCLK frequency between 40 and 1000 MHz.

In the ASUS ROG BIOS, you can configure the SOC BCLK Frequency in the Ai Tweaker menu by first setting the Ai Overclock Tuner to anything else than Auto.

arrow lake soc bclk frequency bios

You can switch between Asynchronous and Synchronous mode by adjusting the BCLK mode option. 

arrow lake bclk mode bios

D2D Ratio

The reference clock is multiplied by the D2D ratio to achieve the final clock frequency. As said, we can only adjust the SOC-Compute D2D frequency.

The D2D Ratio starts from 15X. The default ratio is 21X, which yields a 2.1 GHz operating frequency. The maximum configurable ratio is 40X. The frequency can only be set at boot and cannot be changed in the operating system.

In the ASUS ROG BIOS, you can configure the D2D Ratio in the Ai Tweaker main menu.

arrow lake d2d ratio bios

Arrow Lake D2D: Voltage

The D2D interface isn’t designed to be a very dynamic part of the Arrow Lake architecture. Therefore, its voltage is provided by a static voltage rail.

VnnAON MBVR

The external 0.77V VnnAON voltage rail powers several internal voltages, including the D2D interfaces. Despite it not being referenced that often, the VnnAON voltage is pretty important for Arrow Lake CPUs.  It is part of the voltage multiplexer for many IP blocks, including the cores and ring, typically serving as the floor voltage in power-saving scenarios.

arrow lake voltage topology

I don’t suggest increasing it above 1.0V since it provides little additional benefit for overclocking and performance.

In the ASUS ROG BIOS, you can configure the VNNAON voltage in the Ai Tweaker main menu.

arrow lake vnnaon 0.77v voltage bios

Arrow Lake D2D: Overclock & Undervolt

The overclocking headroom of the die-to-die clock is pretty good: I can easily reach 3.5 GHz with the default 0.77V VnnAON voltage. For higher frequencies it’s hit-and-miss. It’s pretty easy to spot if the voltage is any issue: the debug code will show 00. Don’t worry, however. With 1V VnnAON you can reach higher frequencies and if you’re really lucky maybe even max out to 40X.

arrow lake d2d at 4 ghz

I strongly discourage trying to undervolt the VnnAON voltage rail because it powers so many different parts of the Arrow Lake-S processor that it can quickly cause stability issues. I managed to set the VnnAON as low as 650 mV before the system locked up.

Despite the overclocking headroom, the D2D doesn’t make that much of a difference in real-world performance. With 7-Zip, I saw less than one percent performance difference between 1.5 and 3.5 GHz frequency.

arrow lake d2d performance scaling

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