So my friend has a lga775 motherboard, that came with a p4 3.0ghz processor. I do not know the model off hand but know that the board only supports up to p4 3.2 chips. He bought a 1.8ghz used core duo and stuck it in. The machine wont post with the core duo (of course), but when he puts the old chip back in it posts fine. Is there anyway he ruined this new chip? I ask because I am going to help him order a new MB tomorrow, but he doesnt want to spend the money if the processor is fried. I have never met someone stupid enough to try this so really dont know what the consequences are.
The Core2Duos, although physically fitting in a socket 775, required changes from the previous P4 standard in the onboard power regulation circuitry, and so x and s are overoptimistic. However, I think the OP's friend's CPU was very unlikely to have been damaged.