Re: Justifying A GeForce GTX 275
It's slower in 3DMark Vantage because Vantage is testing ONLY Physx and not much on rendering. In an actual game the GPU is being taxed much more by rendering the graphics and has less overhead available to process Physx.
I did extensive testing with Cryostasis, Unreal Tournament 3, and Sacred 2 by logging 5 minutes of play using Fraps and every time my minimum FPS was higher by 5-10 fps while using the 8800 GTS as the Physx processor. My maximum FPS didn't really change but that's to be expected. While the GPU is being taxed the most by rendering having the Physx processing offloaded to another card helps immensly. I'm confident this will only improve over time as nVidia further optimizes their Physx drivers.
DFI LP UT P35-T2R / C2Q Q6600 @3.0GHz / 8 GB GSkill F2-8500-CL5-2GBPK / EVGA GTX 275 / X-Fi Titanium Fatality Pro / Windows 7 x64