I have the Phenom X2 550 BE CPU. witch I unlocked the quad core on to a Phenom X4 B50. I reducued the the fsb to X15 to get under the 3.0 ghz or i would not even install. I have tried it with it as a B50 and a 550 at 3.0 both fail. The error is Panic(cpu 0 caller 0x2a7e57): kernel trap at 05ceadc07, type 14=page fault, Ill try to include a screen shot when i get off work and can log out of windows The "0" after cpu changes some time 1 2 or 3.