controlling radiator fans based on water temp, not CPU temp?

[Kalmus]

Is there an ideal way to have the fans connected? I am finally finishing up my custom loop build with this board, and noticed that with the fans running off the CPU_Fan header, they ramp up and down needlessly with CPU load.

Since it would make more sense to increase the radiator fans based on water temperature, but a fan needs to be detected on the CPU_Fan header to boot, should I connect one of the case fans to that CPU header, and move my fan splitter to a different fan header that can adjust speed based on a thermal sensor input header instead?

I just ordered a water temp sensor to add into my loop hoping to be able to set this up somehow, so hopefully that idea will work. What do you all suggest?

[pndiode]

For the random fan speed changes due to CPU load try using the CPU Fan Step up and CPU Fan Step down adjustments in BIOS.

[Kalmus]

pndiode wrote:
For the random fan speed changes due to CPU load try using the CPU Fan Step up and CPU Fan Step down adjustments in BIOS.

Thanks! I will try fiddling around with those settings and see if that helps.

Would that be a better option than what I had suggested of connecting a case fan to CPU_Fan, and connecting the radiator fans instead to a different header that will allow adjustment based on input from a thermal sensor in the water cooling loop?

[pndiode]

I would try using the CPU Fan Step up/down in BIOS for fans ramping up and down due to CPU load, because adjusting radiator fan speed based on water temperature is not going have an effect on keeping your other components cool.

[jab383]

Controlling radiator fans by water temperature works like a champ - my 24/7 rig does that. No unneeded whoosh every time CPU load steps up.

Any 10K-ohm temperature sensor will work. There are many makers and brands. Frozen CPU carries many to choose from.

Put a temperature sensing plug in an unused port at the radiator intake, or maybe add a 3- or 4-port coupling that can hold the sensor. Either way, I suggest the radiator intake is the highest temperature in the water loop and is the best place to control the radiator fan. Connect the sensor to a motherboard temp monitor header and set a chassis fan header to be controlled by the water temp monitor.

Note that in the BIOS monitor tab, the CPU fan header can be set to IGNORE. No more nagging. I have my 24/7 and testbench rigs set that way. I also think that BIOS is the best place to select fan control profiles or set your own custom profile -- less load on the cpu while running.