Installed a Opteron 170 and it crashed my comp

Hey everyone I just bought a opteron 170 dual core for my comp. The socket is a 939 .I upgraded from my old athlon 64 3800 to this one. I put the processor in and it boot’s up just fine but whenever I try to run a program it crash’s. So I put my old processor back in and everything work’s just fine as usual. I have a MSI k8n-neo4f pcb 1.0 motherboard, a 250gb SATA Drive, a 7600gt and a 650 watt Thermaltake Power Supply so I’m sure it wouldn’t be a power issue either. I could try putting the opteron in another mobo to see if it’s a processor or mobo issue but other than that I’m clueless as to what it could be please help!!!