UEFI Fan Control Failing

[jgkurz]

Hello, I just purchased an ASRock 990FX-Extreme4 motherboard for use with an AMD 1090T processor. Everything is working well except for fan control. I would like to use the UEFI fan control capability to manage the CPU fan and rear chassis fan. I'm on the latest bios version which is 2.0. The system is used as a VMware ESXi server so the fans cannot be managed by the O/S.

I have enabled the cool&quiet setting and made sure both the CPU and chassis fans are set to automatic. The system temp reports between 40C and 47C and fan RPM's every time I check. I set the temp threshold to 60C and the fan level to 1 which should turn the fan speed down significantly. Unfortunately the fans continue to run at max speed no matter how I set the level or temp threshold. Both fans are PWM so I am at a loss on how to fix this. I have confirmed my setting are applied before I exit.

Any suggestions?

Thank you!

[parsec]

Both fans are four pin PWM fans, correct? Stock AMD heatsink, or something else? The case fan came with the case, or you purchased it yourself?

Are the fan settings you set in the UEFI, Automatic, Level 1, Target Temp, set to those values when you restart and check them again? They don't change in between boots?

The AXTU Utility, which in part can control the fan speeds, is not installed? If it is installed, it may be auto-running, and its settings will override the UEFI settings. The UEFI settings for fans are not automatically also set in the AXTU fan control.

[jgkurz]

Both fans are four pin PWM fans, correct? Stock AMD heatsink, or something else? The case fan came with the case, or you purchased it yourself?

Are the fan settings you set in the UEFI, Automatic, Level 1, Target Temp, set to those values when you restart and check them again? They don't change in between boots?

The AXTU Utility, which in part can control the fan speeds, is not installed? If it is installed, it may be auto-running, and its settings will override the UEFI settings. The UEFI settings for fans are not automatically also set in the AXTU fan control.

Looks like I have 3wire fans. Thanks for the response. I guess I need to understand the difference between 4-wire PWM and 3-wire.

[synack]

3 wire can vary speeds but it is "resistive" as in the 12v power line to the fan has variable resistance which changes the current and voltage to reduce the fan speed. it's not very precise but it is workable. on your MB, cpu_fan2 and chasis_fan2 and 3 are 3 pin and function in this way.

4 wire sends PWM pulses to vary the "duty" to control the fan speed. this is a much more precise way to control a fan. CPU fan 1 and chasis fan 1 are 4 pin fan connectors. The 12V line stays at a constant 12V.

while it is very possible to connect a 3 pin fan on a 4 pin connector, you lose the "variability" of the fan. so putting a 3 pin on a 4 pin connector will always produce a "full on" or "full off" condition. This is due to the 12v line always being 12V on a 4 pin connector.


Try moving your fans to cpu fan2 and chasis fan2/3 and setting the speeds that way.

Syn.

[parsec]

You'll be fine using any of the Chassis fan connectors with those fans, and setting them to Automatic, etc in the UEFI. If the two fans are different, each will likely need a different setting for initial speed, fans can vary quite a bit.

I don't think CPU Fan 2 will change speeds correctly, if nothing is connected to CPU Fan 1. CPU Fan 2 is synchronized with CPU Fan 1, but if a four pin PWM fan is not on CPU Fan 1, CPU Fan 2 will do who knows what?

[synack]

4 pin fans would be better obviously. I was suggesting the OP to just give it a try and see what happens. It doesn't cost anything to try.

[parsec]

Syn, I agree with you. I'm just not sure the fan control will work from CPU Fan 2 if nothing is on CPU Fan 1, just an FYI for the OP. Plus his board's fan control seems different than mine, which has a Manual mode for setting the standard fan speed, but is still changed automatically on the CPU fan.