Need help choosing a cost effective video card

[thermoelectro]

I'm looking for the most cost effective video card to pair with my p4 3.2 ghz for running bioshock. Currently I'm running a 6800 GT. My problem is that most of the benchmarks run by websites use dual core processors so I have no idea how to interpret their data. If there was a website that benchmarks older machines with newer software, that would be nice too. Which card would give me the most perfomance gains without totally bottlenecking my processor? My budget is around $250, but I would preferably like it to be under $200 if possible.

edit: I have a pci-express slot, not AGP.

[cputeq]

One of the best cards in that range is a 1950Pro/XT if you can find one in stock.
No directX 10 though, but good speed.

[Rage3kMoiz]

Agreed. The X1950PRO or the 7950GT will give you the best performance for your CPU.

[thermoelectro]

What kind of perfomance gains should I expect if I went with either of those cards or say a 7900GS? Or is there simply no way to formulate an estimate?

[Rage3kMoiz]

Try using Tom's Hardware's GPU charts. They should give you a rough estimate of the difference in performance, which is\should be very great BTW.

[secretanchitman]

7950GT i would think, possibly even an 8800GTS 320MB.

[Dazed and Confused]

512mb X1950XT , Problem solved

[fujimitsu]

I would get an x1950xt, 512mb can be had for under $200 on sale, the 256mb can be found for $150 sometimes.
I upgraded from an x1950xt 256, to an 8800gts 320mb, if you have the $279 and can wait for a $20 rebate, the 8800 is my choice.