Upgrading power supply and video card

[picison]

I have the Dell XPS 435 MT and have had it for a few years now, needless to say it's getting a bit dated, I have already ordered a new power supply because the one the pc came with didn't leave any room for upgrades. The power supply is 600W and confirmed to work with my pc. Now I just need to pick out a Graphics card, I would like to have one that of course survive on 600W and also play the newest games like battlefield 3 and such. I don't want the best though, I'm trying not to spend to much money. It might also be helpful to get a ATI radeon graphics card since that is what I have now and have all the drivers for, but I'm not sure if it would be hard or not to install a Nvidia card or not so maybe you could help me there too.

Addition Specs-

8 GB of RAM
Intel Core I7 920 @ 2.7ghz
64 bit OS

Cut to the chase-
I need a new graphics card to run the newest games on the market, I have a 600W limit, I would prefer a ATI card, I'm on a budget.

Thanks for the help, Picison

 

[geofelt]

A quality 600w psu will run any single gpu graphics card made today.
That is up to a 7970 or GTX680.
Here is a handy psu needs chart:
http://www.realhardtechx.com/index_archivos/Page362.htm

Some of the high end cards are long, perhaps 11" so measure.

A AMD replacement would be easiest since you will keep the same driver.
But, if your game is BF3 then it seems to do better with nvidia cards.

To change drivers, uninstall the old video card, and also uninstall any amd software.
Possibly, you might want to also run a driversweeper program.

With no driver, a video card will run in a low res mode, like 680 x 400, so you can still do things.