This is probably the biggest single reason why I shy away from OEM cpus. I never seem able to assemble and test components straightaway, partly because I don't have oodles of spare kit lying round, partly owing to sheer sloth. So if I did receive a bad cpu, I wouldn't know before it was too late. I've an Athlon X2 3800+ OEM which I've not been able to POST, and I don't know if it's a bad chip, or my board needs to have its BIOS flashed, or... If the chip is bad, at this point there's nothing I can do.
This might be the time to ask why OEM cpus have no warranties. I've read that the manufacturer considers the OEM to be the retailer, ie the manufacturer has no obligation at all to the end consumer. But hard drive manufacturers consider the system builder (us) to be the OEM, which makes much more sense, thus we can get OEMl hard drive warranties. Would it be such a $ drain for the cpu manufacturers to provde one-year warranties to us? They could still stipulate that overclocking would void the warranty, etc.