Im afraid not my friend. You can however SLI different brand/manufacturer using the 81.98 driver, but you as far as I know you cannot SLI card with different models/gen.
Ex: BFG 7800 GT compatible with Evga 7800 GT
note: the same gen/model 7800 GT
7800 GT is not compatible with 7800 GTX, 7900, 6800, etc.
Beside with a good cooling system like water cooling you can overclock a 7800 GT SLI to a performance similar to that of a GTX but however you cannot increase/overclock pixel shader. GT has 20 and GTX has 24.
But who knows maybe nvidia is gonna release a new driver that would enable two graphics card of different manufacturer and model to run together.
That's a good thing about ATI being able to run x1800 crossfire with a X1900 crossfire ready.
But one good thing about the 7800 GT is u can snag one for around $280-$340 half the price of a decent 7800 GTX. Then you can get a water cooling system with it.
To avoid issues, just try to buy the exact same card.
BTW, running 2 7800GT's in SLI is the same thing as 1 x1900xt. I recommend you sell the GT and buy the ATI card.
To be exact, that's exactly what I just did. I had 2 7800GTs in SLI and sold 1 so far -- the other one is in negociations...
My goal 1 x1900xt or a "7900GTX" that will be out soon.
You are about to answer a thread that has been inactive for more than 6 months. If you still wish to proceed, please ensure that your posting is original and does not duplicate or overlap any prior responses to this thread.