I know that my question might be dumb but as I don't really know how DirectX 11 and Tessellation are implemented in to a system, my question is if I add a GTX460 or GTS450 to my system (In my sig) would that let me keep my quad SLI power and add DirectX 11 and Tessellation or would it just be a waste of money?
You'd be reliant on the version of DirectX supported by your main graphics cards. So, while you could add a GTX460 into your system for PhysX, you wouldn't get DirectX11 graphics as a result of it. The idea with DirectX11 was that DirectX10 hardware COULD use the features using trickery on the driver/design end, but I honestly have no idea how you'd check that. For example, DiRT 2 uses a DirectX9 and DirectX11 engine for different hardware types, but nobody knows if DirectX10 cards use one or the other. In all seriousness, though, I don't think I'd ditch that much power for the extra features. Don't think you're missing much.
So are you asking if you keep the 295 and add something like a 460 would you get Dx11? Sorry im a bit slow If so i think you would still have Dx10 as the 295 would be your main render card.
I say, wait for the next Nvdia or ATi card and replace your main GPU then. You'll get DirectX11, and way better performance increase from what you have now. And at leats by then, you should maybe, hopefully, perhaps, be able to use a game that actually support DirectX11 natively (unlike ""DX10"" games, that is all made in DX9, but has a water spill in one room in the entire-game that is made in DX10 and get crap performance in that room due to a lack of any optimization, just to go "WOOOOOOOOoooo DX10! Buy our game!".
