In windows, it says AMD Phenom II X6 1100T processor, yet in cpu-z, or any other program that shows the cores there are only 3 cores. How could this be? I just had a 550 BE with the 3rd core unlocked, could that be the problem?
In msconfig, under the boot tab, click advanced options. If its checked, uncheck number of processors. Did you check about the settings in the bios from the 550?