I have a amd phenom II x2 550 and was running on Gigabyte 880GM D2H for few years until the other day stopped working, the fan and lights came on but no beeps and no display... I had a spare MB (gigabyte 880GMA UD2H) which all seems to be working BUT I noticed when I reboot the "POST" shows phenom II x2 550 most of the but sometimes it shows phenom II x4 B55... I dont have any overclocking or cores unlocked, its all stock and default setting... when it picks it up as X4 I usually end up gettin BSOD as windows starts loading.. maybe its the CPU after all?