What voltage should a CPU fan be at?

[mr_fishbulb]

I was trying to fix a machine last night and found out that the CPU fan power plug on the motherboard wasn't supplying any power. When I hooked up one of those molex pass-thru things and plugged the CPU fan into there, the machine boots fine.

Then I remembered I'd set the voltage trick on the molex to 7v when I was using it with my old case fan.

Should I swap it back to 12V to use it full time with the CPU fan?

 

[llwyd]

i see no reason why that would allow the machine to boot, there is probably a problem with the 3pin. what type of fan was is? because sometimes 3pins dont detect them and the BIOS prevents boot for overheat protection. But yea, running it at 12v off a molex is fine

 

[Raging]

if sound is an issue then run it at 7v and stress test the cpu to see if the temps get too high.

but i would suggest running it on 12v for maximum cooling.

cheers.

 

[mr_fishbulb]

I'll turn it back to 12V then. Thanks.

I'm not exactly sure why it wasn't boot. Everything else came on - graphics card fan, hard drive, dvd drive etc but no fan. So I tried it with a spare fan and that fan wasn't working either so then I tried this molex doodah and it seems alright now.

I don't think sound will be a problem because it was probably running at 12V before it broke anyway.

 

[FragTek]

by default all fans in ur system should be running at 12v unless uve added a resistor or what have u to knock down the voltage to get some peace and quiet.

I definitely recommend that u always run your cpu fan at 12v however (unless it happens to be something like a tornado, lol)

 

[NickS]

Weird issue you got there. Maybe the board's fan header cant handle the full 12v from that fan?

I have my CPU Fan auto adjust to my temps in MSI Core Center

Nick

 

[Raven]

some fans draws more power than the motherboard can handle and it can show itself in a couple of different ways.