I have the same motherboard/cpu (retail) combo that you have. It's currently running at XP 2000+ @ 1.68GHz. I just went to the BIOS, changed CPU Clock to 133 and CPU Ratio to 145 under Frequency/Voltage Control menu. I also bumped up the CPU Core Voltage to 1.8V. BTW, I'm just using the heatsink/fan that came w/ the retail CPU. My CPU temp is at 39C idle. 38C idle if I set it to XP 1900+. 🙂