I have a problem with my AMD XP 2600+. The CPU is not older than one month and wasn't overclocked ever but my Mainboard (Asus A7V8X-X) crashed during the last weeks and I had to buy a new one. I have installed the new mainboard and it should normally work but the CPU doesn't work well.
When I clock the CPU @ 2083 MHz how it is normal computer doesn't boot up... I get anything on the screen. After reset still nothing happens. When I switch the computer off and start it once more the bios screen appears. After clocking the cpu @ 1667 MHz everything works... I don't know why but this are more than 400MHz less and you can imagine that I'm not very happy about this situation.
The rest of my system consist of:
Asus A7V8X-X (new)
256MB Infineon 333MHz
ATI Radeon 8500 (BBA)
Enermax 356W power supply
I hope someone could help me... my theory is that the CPU is damaged by the crash of the mainboard because the cpu doesnt accept a FSB of 166 MHz .... (now it runs @ 133MHz FSB)
It could be a heat problem. Did you put the hsf on right way round? Is the heat sink tight to the cpu? Try to wiggle it and see if it's really loose. A little loose is ok, but if it turns more than a few degrees, that's your problem. Wiggling it just after you've shut down may help to even out the thermal paste as well. Speaking of which, how did the thermal interface look before you put the proc onto the new board?
I just got the same psu so I hope that's not the problem, but if it's more than 2 years old it could be starting to dry out. If it is old see if you can borrow a different psu for tests.