Any harm in plugging a PSU fan directly to the Mobo?

[unclened]

I'm using an spare PSU in my son's pc but the fan is pretty loud, so I've replaced it with a 120mm be quiet fan and as it's 4 pin (PSU fan was 2pin), I've plugged it into a case fan header on the Mobo. So far the fan has been noticeably quieter but I'm wondering if there were any long term downsides to this approach? I have programmed it so when the CPU or GPU are under load, it kicks up a gear or two as a proxy for taking an actual temp reading from the PSU itself.

 

[robj20]

Why not just wire it into the PSU so that it can control the fan.

 

[unclened]

PSU is 2 pin only, unless there's another way?

 

[CaptainAverage]

Interesting solution. Have you any way of measuring the temp of the PSU to be sure the fan kicks in at the optimal temp?

 

[robj20]

PSU is 2 pin only, unless there's another way?

Yes use the 12v(red) and 0v(black) wires to the PSU. Ignore the other two wires on the fan PWM and speed.

 

[unclened]

Interesting solution. Have you any way of measuring the temp of the PSU to be sure the fan kicks in at the optimal temp?

I was thinking I could use an infrared thermometer and calibrate the fan. Right now its on by default at a low speed and then if either the GPU or CPU hit a threshold, it gradually ticks up as well.

 

[gman]

I've got a Corsair RM750i and the fan ticks over at about 740 rpm. The temperature even when gaming doesn't go up by much. What PSU are you using, some come with monitoring software?