Hi folks

I've recently installed a new ASRock G31M-S R2.0 motherboard whilst building a new system. For those of you in the know, it has a 4-pin connector for a PWM fan. I'm using a FOXCONN PWM 12V .65A fan and I've tried at least 3 800 MHz FSB Pentium 4 CPUs, correctly installed with thermal paste.

The problem is the CPU fan noise. The BIOS allows the setting of 3 speeds with an associated temperature. If I select the slowest speed and the highest temperature, the fan is still noisy. And it's not the bearing going, it's the fan speed and volume of air being shifted. The only way I can get the system to run without sounding like it's lined up for take-off is to install and configure Speed Fan but that means the fan runs at around 5000 rpm until the system boots into XP. However, once SF has kicked in, the fan can be controlled down to around 1600 rpm and the fan can hardly be heard.

I'm wondering if this is normal. Troubleshooting steps I've taken so far are to try different CPUs and I've also upgraded the BIOS from 1.19 to 1.20. (Although new, my vendor has told me that as I've upgraded the BIOS then it's a different motherboard and he won't even allow a return to check it out.) My thoughts are that the motherboard is not flexible enough to cope with instantly varying temperatures (hence the 3 speed bands), my fan isn't really compatible with the motherboard or that there's a problem with the temperature-sensing circuit that requires a third party, OS-based solution, although I might have contradicted myself there. Before I spend more money on a different cooler sorting what might not actually be a problem, I'd be grateful for any advice is out there.

All the best