I recently bought the AMD Phenom II X6 Thuban 1055T, and the ASRock 870 EXTREME3 AM3 AMD 870 SATA 6Gb/s USB 3.0 ATX AMD Motherboard. The processor fit well, but when I tried to apply the stock heatsink, it will simply not attach to the plastic attachments on the motherboard. Am I doing something wrong or are these parts incompatible or faulty? This is my first build, please help.