IMO, are you sure that your motherboard is only AM3 compatible, and not AM3+? It's been a while since I've seen a board that actually didn't call itself AM3+, even if you would need to do a quick BIOS update. If that is the case, you could look at some of the new FX chips that will still meet the TDP limit. The only case I can think of where this would be unlikely is if you have a Dell or other OEM system as a platform. In that case, I'd go for the Phenom- as someone else said here, better architecture.