I managed to get a fairly good deal on a EVGA Nvidia GTX 480. However, I'm now having second thoughts. I've already put an ATI 5850 in my machine, so I have a pretty recent high-end card. Should I keep the 5850 and sell the GTX 480 for cheap, or should I do the opposite? I haven't opened the 480, so I'm fairly sure I could sell it on, but it is so tempting. What would the difference be in games? Thanks.