Need to upgrade my computer but need help!

What type of PSU are you getting? 7900GT IMO is worth every penny for it performance.

the company that makes the PSU is the important factor, not the total wattage.

whatever video card you want to buy, read the manufacturer's specs for power supply amperage/current requirements. this is what cheap power supplies lack, and good power supplies provide.

don't worry about the wattage, worry about the amperage. 12v rail (or rails) are most important. the total wattage of a PSU is calculated from all power rails, but each PSU provides different power levels on each rail which will alter the total wattage but may not provide that power where it is needed.

hope that clears things up a bit.

that didnt really clear things up i aint all that great when it comes to this stuff. can you suggest a good 7900? (newegg or other site link) Like for example this card http://www.newegg.com/Product/Product.asp?item=N82E16814133166 is it better than the evga or what? i mean i just really need help picking out a good 7900 and fast thanks!