No POST on XP Restart???

I have my 820 OC'd to 3.55 with a FSB of 255 and 1.38V. Idle temp is 32, load is 44. Everything looks to be in order. CPU passes CPUstabtest and Prime NP, but when I restart my PC (XP Pro) it goes through the shutdown sequence like normal. When XP shuts down though and go to the black screen before POST, the PC just sits there and I have to do a hard power down to get it to restart. I turned my BUS speed down to 240 and the problem seems to have stopped. What could possible cause this issue?? The CPU seems fine on all accounts. Am I missing something???

What motherboard are you using?

Gigabyte 945P-Pro.

I am not familiar with that board and haven't used Gigabyte in a long, long time. With that said, some board just have annoying quirks that manifest themselves when we OC our systems. Normally these can only be fixed by the manufacturer through bios updates, if at all.

First thing is check to see if there are any bios updates. If there are none or it doesn't help, I would look at voltage settings. You said it passes prime but maybe go up a notch on the Vcore just to see. See what other voltages are available and tinker with them a bit. Only adjust one at a time so you know what fixes it if anything does. It may be unfixable or could be something simple like setting or a USB device plugged in.

Good luck.

I think the voltage did it. I tunred it up to 1.4 and now she restarts like a champ! I also lowered the multiplier on my memory and turned up the latencys a little! Ram Dual-primes last night for 7 hours and both came back clean! Looks like I'm good!

You should also try chipset Voltage. I dunno how that is with the new PCI-X boards but I need to raise AGP Voltage a notch otherwise it won't sometimes do a warm reboot @257FSB here...