I have the opportunity to pick up a Geforce 460 for $120. I was wondering how much of a performance difference I could expect to see on my system upgrading from 2x 8800 GT running SLI. I'm thinking about this purely in terms of gaming performance.
System: Dell XPS 630i
Mobo: nForce 650i SLI
CPU: Q6600 overclocked at 3.150 for each core
Memory: 2x 2GB Corsair DDR2
Current GPUs: 2x 8800GT 512MB
Potential GPU: 1x EVGA Superclocked Geforce 460 1GB
Display: runs at 1440x900
Side question: If I do upgrade to the 460 am I able to use one of the 8800GTs as a PhysX card?
At stock it will be a slight upgrade but when OCed it will pull away nicely. Honestly though at your resolution the performance difference probably wont be all that noticeable as 2 8800GTs should already be very good. It will however remove any SLI scaling/compatibility issues, give you DX11 compatibility and use much, much less power. The GTX 460 uses 50w+ less under load and over 5 times less power at idle. You will be able to use the 8800GT as a Physx card which isn't a big deal imo but you can also use the slot for another GTX 460 at some point if you upgrade your monitor.
Hell, even if you don't want to use the card for $120 you can always just put it on Ebay and make $100.
The only reason I'm not thinking about two 460s running SLI is that my mobo only does 1x PCIe 16 or 2x PCIe 8. It won't do 2x PCIe 16 so I'm worried I'd lose basically all the benefit to scaling issues. Especially since this is a PCIe 1.0 mobo.