Video Card Question

So, it’s time for the ol’ computer to get a video card upgrade. Problem is, I have very little idea as to what I’m doing.

I know that I have a PCI-e bus type, and that I’m currently using a Radeon x700 with an ATI chipset. I further know that I am not interested in another ATI card – I’d much prefer to go with a nVidia chipset.

This page is what’s confusing me the most. The GeForce 7900 shows as having a 14x improvement over integrated graphics, as opposed to the 13x for the 8600. Does this mean that the 7900, even though it’s a series earlier, has superior performance to the later 8600?

When a card says it’s using DDR3, as with this card, does this mean I need to be using DDR3 RAM in my computer to realize its full potential? I currently have two channels of DDR2 RAM, would this negatively impact the performance of this card?

And finally, say I did purchase the last card there that I linked – what sort of difference in graphics performance could I expect to see in terms of picture quality, framerate, etc etc, over my current x700? For the record, my computer only truly gets put through its graphical paces when I play my various games – Civ IV, Medieval Total War 2, World of Warcraft, Oblivion, and the like.

Hottest at the moment are the 8800GT cards.

This PC has a 8600GTS, which is a substantial improvement on the 7600 GS and 7800 GS I have in two of my other PCs. Sorry, I don’t have figures to hand, and you’d need to adjust for processor speed and XP vs Vista, but this should help: the 8800 is double the performance of the 8600.