Gamingforce :
So, should i use 3 Asus GTX 770s 4GB in triple SLI or 1 GTX 780 Ti/GTX 690? And would the GTX 770 memory stack up so that i have 12GB?
First of all, tri-sli is generally not recommended, as you'll have a lot of latency and frametime issues. Then there's heat, power, noise etc etc. Regular dual SLI is the max people should get. Besides, a third card will not increase the performance in a way the second card does. You pay the price of a full gtx 770 but gain only a tiny little bit of performance, it's really not worth it at all. Second: the memory will NOT stack up, eventually you'll be left with 4gb of effective memory. Third: 3 770's are waaaaay more powerful than a single 780ti. Fourth: Don't go with the 690, it's a previous generation GPU and from what i've read, a 790 is on the horizon. Fifth: The price you'd pay for 3 770's probably will be about the same as 2 780ti's and you'll have a MUCH better experience with those. way less issues and driver problems.
So my recommendation is: dual 780ti's
Joni