Help upgrading my Dell XPS 730

Hello, I have a Dell XPS 730 that came with a Nvidia 9800gt x2 SLI I would like to upgrade the card as it is failing. I bought the unit in 2008. I have ugraded to windows7 64 bit and 8GB of Ram. Can you give me a suggestion as to a replacement that will perform better at a reasonable cost. Thanks for your help. I have no particular loyalty to Nvidia meaning that an ATI graphics card that outperforms at a reasonable price is something I would look into. Thanks, Jonny

What CPU do you have and what PSU(brand, watts and 12V rail Amps). What resolution do you play at?
For resolution up to 1920x1080 i would recommend a 6950 1/2Gb video card. 2 Gb model might have an edge when playing with high AA. Sometimes in certain games 1Gb of RAM is not enough.

If you prefer Nvidia a GTX560 Ti(must have the "Ti" ) is close to a 6950 performance wise but it is more power hungry. Eider one is a good choice.

You haven't posted a price limit so i posted what i think is the best price/performance ratio video card. If these models are too expensive a 6870 is also a good card for 1080p resolution.

6950: http://www.newegg.com/Product/Prod [...] 0HD%206950
6870: http://www.newegg.com/Product/Prod [...] 0HD%206870
GTX560TI: http://www.newegg.com/Product/Prod [...] 28Fermi%29

By the way, what i posted will be a few times more powerful than your 9800gt SLi.

so this unit came with the single card 9800GX2 and since it's a dual card it runs better in SLi or,
you actually have 2 9800GT's and run them in SLi.?
please elaborate to make sure.