The 8800GTX is still the fastest you can buy today. The dual slot cooler(good) just means that the next slot to your pci-e slot will not be useable for anything. This is not normally any problem unless you have fully populated all the slots in your mobo. What you DO need to check is room for the length of the card in your case. It is 1.5" longer than normal, I think a total of 10.5". Also it requires two pci-e power connectors, and a PSU with about 30a on the 12v rails total.