I just bought a new computer and was hoping to upgrade the video card. My question: Is there a bus speed (or something) pertaining to the motherboard that could limit the performance of a higher end video card? I ran a program that said my bus clock? was only 333 mhz. I think my Front Speed Bus is 1333mhz, and all of these different numbers have me confused. I was thinking of upgrading to a radeon hd 4890 (from a geforce gt220). Any advice or thoughts would be greatly appreciated!