ElmorLabs EFC-SB SkatterBencher Edition

The Easy Fan Controller SkatterBencher Edition (EFC-SB) is a customized EFC resulting from a collaboration between SkatterBencher and ElmorLabs.

Order EFC-SB

https://www.youtube.com/watch?v=jq2iVR90olo

Easy Fan Controller SkatterBencher Edition (https://www.youtube.com/watch?v=jq2iVR90olo)

Table of Contents

EFC-SB Product Overview

The EFC-SB, or EFC SkatterBencher edition, is a customized version of the original ElmorLabs Easy Fan Controller. I’ve used since SkatterBencher #26. The base product functions and features are the same as the original EFC, with here and there a tiny improvement.

The most obvious difference is that this EFC version comes in the SkatterBencher color scheme: yellow, white, and black.

The EFC-SB sports a white PCB with gold markings and prominently features a slightly modified SkatterBencher logo. The black power and fan connectors contrast against the yellow I2C and external temperature sensor connectors. The configuration button is also black, and we changed it to a white LED with a yellow lens. The EFC-SB also has a white 3D-printed back cover to protect the soldering points.

The EFC-SB also has two new features: T_max LED and RPM_detect LED.

T_max LED is a function that warns the user in case the fan duty cycle reaches 100%. Suppose you map the fan curve to the water temperature. In that case, the water temperature has reached the maximum allowed value. The warning consists of a unique LED lighting pattern.
RPM_detect LED is a function that warns the user in case the reported fan speed is too low considering the set fan duty cycle. Practically, it may indicate no fan is present or that the fan is broken. The warning consists of a unique LED lighting pattern.

Last, we’ve expanded the accessories included in the package. The EFC-SB comes with two yellow waterproof and two regular black flat-tip thermistors. It also has a different I2C cable with a yellow, white, and black color scheme.

The first fifty units of the ElmorLabs Easy Fan Controller SkatterBencher Edition’s initial production batch (EFC-SB) are available from the ElmorLabs web store. By purchasing an EFC-SB, you support my work directly, and any support is highly appreciated!

User Guide

EFC stands for Easy Fan Controller and provides a simple and straightforward way to manage your system fans. I’ve been using it since SkatterBencher #26 and even covered it in a dedicated blog post. Setting up the EFC is also pretty straightforward. Simply plug the fans into the fan headers, the power into the power connector, and if you are using an external temperature sensor plug that into the temperature sensor header. Then use the button to navigate through the configuration menu.

Short pressing the button once allows you to select between 3 menu items: fixed, low, and high. Fixed lets you set a fixed fan duty cycle setting, and low/high lets you configure a lower and upper ceiling for the temperature-controlled fan curve. As you cycle through the menu items, you will find the upper LED go from least bright to most bright in 3 steps. This indicates which item is currently selected: lowest brightness is Fixed, medium brightness is Low, and maximum brightness is High.

Long pressing the button after selecting one of the 3 menu items allows you to choose one of three options for each menu item:

Fixed can be set to 30%, 60%, or 100% fan duty cycle.
Low can be set to 25, 30, or 35 degrees Celsius.
High can be set to 40, 50, or 60 degrees Celsius.

As you cycle through the options, the lower LED goes from least to most bright, indicating which option is currently selected. After selecting the option, you do not have to do anything to apply the setting.

When you set a low and high point, the EFC will complete the fan curve using a linear function. So, in total, the EFC supports 9 different fan curves mapped to a temperature sensor and 3 fixed fan curve.

Default Configuration

By default, the EFC-SB maps the fan curve to the external temperature sensor (TS1). The selected fan curve is Low=25 and High=40. That means the fan will start to operate when the temperature is 25 degrees Celsius and reach its maximum RPM when the temperature is 40 degree Celsius. The fan duty cycle is 30% at the low and 100% at the high point.

The T_max warning is enabled, and the LED will light up if the external temperature is 40 degrees Celsius or higher. The RPM_detect warning is also enabled to warn the user when the reported fan speed is less than 200RPM if the fan duty cycle is 80% or higher.

This is also how I use the EFC in almost all my SkatterBencher guides. The main advantage of this configuration is that it gives me a good indicator of whether the cooling solution is saturated.

Suppose the CPU is at TjMax, and the water temperature exceeds 40 degrees Celsius. In that case, the fans are at maximum speed, and thus the cooling solution is saturated. Improving the cooling solution by adding radiators or changing to more powerful fans would be the right action.

Suppose the CPU is at TjMax and the water temperature is below 40 degrees Celsius. In that case, it means the cooling solution is not saturated. Therefore, to improve the CPU temperature, you may enhance the thermal transfer of the CPU heat into the loop by changing the thermal paste, delidding, or changing the water block.

EVC2 Extension

The ElmorLabs EFC-SB can also be connected to the ElmorLabs EVC2 to extend the functionality. The expanded functionality includes monitoring and logging the temperatures, fan speeds, and fan duty cycle. You can also use it to turn the Easy Fan Controller into a more Advanced Fan Controller with more options to customize the fan curve.

First, connect the EFC to the EVC2 using the I2C header to do all this. Then connect the EVC2 device to a USB port on your motherboard.

Now, download the EVC2 software from the ElmorLabs website.
Next, open the software and select the I2C bus connected to the EFC. In my case, that’s I2C1
Click on “Find Devices,” and the ElmorLabs EFC-SB should be detected automatically.
Navigate to the ElmorLabs EFC-SB item in the menu; now, you have access to all the extended functionality of the EFC.

The extended functionality includes:

Switching between fixed mode and temperature control mode
Enabling Fan Stop
Changing the temperature source between the internal and external sensor
Adjusting the fixed fan duty from 0% to 100% in .625% intervals
Adjusting the temperature control parameters
- Low and high temperatures from 10C to 60C in 0.1C intervals
- Low and high fan duty cycle from 0% to 100% in .625% intervals
Switching between different types of temperature sensors
Changing the I2C address of the EFC-SB
Changing the RPMdetect warning fan RPM speed
Changing the RPMdetect warning fan duty cycle
Enabling the Tmax warning
Store a custom configuration to the device, which will be loaded on power up.
Monitoring and logging of both internal and external temperatures,
Monitoring and logging each fan’s speed
Monitoring and logging of the Fan duty cycle

To enable monitoring, simply check “Monitoring” in the software. To enable data logging,

Right-click on any of the graphs that you would like to log the data of and select Add to Data Logger.
Navigate to the home menu and click Data Logger.
Ensure that the data points you want to log are selected.
Click File and select a folder where you want to save the data log.
Then click Start Logging.

The data logger creates a simple CSV file that you can import into, for example, Excel and make your charts.

You can also use the data logger to include the monitoring information in HWiNFO. You follow the same steps to add the information to the data logger but check the Hwinfo export option. Then click Start Logging. Now you can open HWiNFO, and the EFC-SB items should appear automatically.

EFC-SB Bundle

The ElmorLabs Easy Fan Controller SkatterBencher Edition (EFC-SB) comes with the following items:

1x ElmorLabs EFC-SB (circuit board)
2x water thermistor (1m, waterproof tip, yellow cable, yellow connector, B=3950)
2x regular thermistor (1m, flat tip, black cable, white connector, B=3950)
1x I2C cable (XH2.5 3pin to 2.54mm 1×3-pin, 0.5m, yellow, white, black cable; black connector)
1x 3D printed back cover (white)