Fan speed slows down on heavy CPU usage

[ledd]

Hey everyone.

I'm overclocking an Intel Q8200 from 2.33 GHz to 2.89 GHz, first time try, be gentle... Info follows:

Asus P5QL-Pro Mobo

CPU Voltage: 1.26
FSB: 412 MHz
FSB Strap to NB: 400 MHz
Rated FSB: 1648 MHz
Memory at 1098 MHz 6-6-6-18 (they're DDR2 800 modules)
Geforce 8600 GT (silent model)

500 W Power Supply
Stock cooling (yes ugh)

The problem I'm having is that anytime I use the CPU intensively the fan drops the speed and the CPU temps go up maybe 15º C.

Thanks in advance.

 

[Fruity]

Can think of a few things that might cause this. Best case scenario is that the fan settings are fubar in BIOS - try setting everything to permanently run flat out and retest. If the fan speeds don't drop then that's good news.

Alternatively, it could be a dicky PSU, a bad fan connection on the motherboard or a bad fan. If you are truly disgusted by using stock cooling, which you should be , then replace with something decent and retest. If that doesn't show any improvements then its time to look at your PSU or mobo.

Probably worth seeing exactly how far your fan speeds are dropping when loading the CPU. Use Everest or similar to keep an eye on it. There will be a little natural variation (100rpm or so at full speed).

 

[ledd]

I've set the BIOS settings to run 100% all the time, disabled all power saving options and etc. Even switched the CPU fan to a system fan port so that there was no speed control.

The fan looks ok, I'm thinking the PSU might be the problem since it's somewhat old (about 3 years now).

When I start using the CPU the fan drops from 2100 rpm's to 1800 ish, I've monitored this with speedfan.

As of right now I can't afford to buy a new 'decent' cooler for the CPU so I'll have to stick with this for a while. Any other suggestions?