It's just like the question says.... If I switch from a EVGA P55 MOB to a Higher End EVGA P55 MOB or A Different Brand will my OEM Windows 7 still work. I am doing so because I am going Crossfire soon..... and while the MOB I have right now has two PCIe 2.0 slots on it.... One runs at x16 and the other one at x4. I would rather have the x8 and x8. If anyone knows for sure that would be great. I heard at one time as long as the chip set (P55) is the same it will be fine. Am I wrong????