Run CPU fan from mobo or PSU?

arf80 · Post by **arf80** » Sun Jan 28, 2007 3:22 pm

I've got an intel 865 series motherboard (socket 478) with the stock HSF. The CPU fan is plugged into the default spot next to the chip, and the motherboard varies the speed of the fan depending on the amount of heat in the system (I can hear it spin way up during games). When I replace the stock HSF with an aftermarket system (Yate Loon 120mm fan), will I be able to plug the fan into the same spot on the motherboard? Will the motherboard be able to control the speed of this fan correctly, or am I better off bypassing the motherboard altogether and running the fan right into the PSU? My only problem with bypassing the CPU fan connector on the motherboard is that the motherboard will think no CPU fan is connected and refuse to start.

Post by **NeilBlanchard** » Sun Jan 28, 2007 5:49 pm

Hello,

The mobo header is probably fine, to do this.

dfrost · Post by **dfrost** » Mon Jan 29, 2007 8:40 am

I agree with Neil. The motherboard header with it's variable voltage very nicely controls the Papst fan on my XP-120 with an Abit 865 (AI7) board. I've also added a Zalman Fanmate on that fan and header, but never bother to adjust it manually anymore. It just acts as a speed reducer when set to the maximum - fan voltage is now ~6-11V instead of the 8-12V that the MB header supplies.

My only problem with bypassing the CPU fan connector on the motherboard is that the motherboard will think no CPU fan is connected and refuse to start.

Yes, it is a good idea to have the fan connected to the CPU header for that reason also. If possible, you may want to adjust the allowable fan speed range in your BIOS to avoid alarms, depending on the fan that you select.