CPU Fan not Spinning

[JJimmyJ]

Hello

I completed a new build for a work colleague last night:
I5 3570k
Gigabyte GA-Z77-D3H
Arctic Freezer Pro 7
Everything went fine, but I wanted to do some last minute checks. I'm glad I did as I discovered the CPU fan (Arctic Freezer) wasn't spinning.
It starts an initial full spin on start-up, but then stops once past the flash screen. I assumed it was just part of the PWM, but I ran Prime95 and the fan would still not kick in.
I've checked bios and it's all set to default. I've changed various fan settings and tried again. This involved changing to manual control, disabling entirely to try and get it to run full speed, but all ended with the same result.
I unplugged the fan pin and tried plugging in the standard intel fan with all bios set to default. The fan spun no problem.
I've checked the Arctic Freezer is not faulty and plugged it into a spare system fan slot. It spins no problem (currently using this a temp solution).
So my assumption is the Arctic Freezer isn't getting enough voltage from the CPU fan header, but I don't understand why.

Anyone had any experience with this before?

 

[trickynickyuk]

if it works in the system fan slot leave it in there and run for a bit and see if it cuts out if it doesnt try putting your exaust fan on the cpu connector and run it like that

 

[JJimmyJ]

Yeah I've got it working using the system fan slot, but I'm one of those people that likes to know why it isn't working and probably won't rest until I figure it out.
Plus, the build is for someone at work so it's not really an ideal solution.
I'll see if a bios flash can work it out. I read somewhere about EasyTune which potentially overrides the settings in bios. Could be causing a conflict even although it's uninstalled.

 

[JonSmith]

This can happen if the fan control type is set to voltage not PWM.

In Gigabyte boards only the CPU fan header has fan control enabled, the system fan either runs at max speed or off. It's probably a settings issue so check again.