4 way sli geforce gtx 770 or 2 way sli 690?

GTX 690 = two GTX 680 GPU's on a single card, a single GTX 690 is about equivalent to two GTX 680s. GTX 770 = basically an updated GTX 680, usually the GTX 770 is 5%-10% faster than a GTX 680. On paper the 4 way GTX 770's will be faster, but in the real world SLI scaling drops dramatically after the 2nd card and the scaling is usually negligible when a 4th card/GPU is added. I usually breaks down to something like this Going from 1 to 2 cards will net you a 75-95% gain depending on the game. Going from 2 to 3 cards will net you a further 30% gain on average Going from 3 to 4 cards will net you a further 10-15% gain in real world application. There's a definitely a point of diminishing returns. I'm not sure what the other is talking about, that answer has little to do with the question you asked.