OEM should always be the same or less than retail. The reason I didn't respond earlier is because the FX processors have around a $60 difference in price between OEM and retail. Why he would want to waste money on an FX, I don't know. Guess there's money to burn. I couldn't give two shits about any kind of warranty (but then again, this is a 600-800 processor we're talking about), because I've never had one go bad/broken. But I do like the retail HSF on my 64 3000+. However, for 65 bucks I'm sure there are better ones out there.
Btw, I *think* OEM procs have a 30 day warranty, but it could be a year or something. I'd check AMD's site.