I think 2 way SLI are pretty optimized these days and are well supported by most games.
The GTX 760 SLI benchmarks proves that at least... even beating 780s and the Tiitan.
And I've never really seen many bad results w/2 way SLI as compared to 3 or 4 way .
4 way SLI for example are way less optimized, that a 2 way can outperform it.
I watched few videos and did some research and these are the infos I've gathered.
I think 760 SLI is pretty worth it, considering the fact that it would only cost around $500 and it delivers enough performance well worthy of its price.
Here's a benchmark video from Newegg (@ 9:08):
http://www.youtube.com/watch?v=KfOtmoxLMXI
: You can clearly see it beats the 780 by quite a lot.
So it's either you go 760 2 way . Or IF you have the money, get 770 or 780 and SLI that instead. But that would go way over $1300 +
You decide if it's worth the price. But it's only worth it to get a higher model if you'll SLI it as well.
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Oh and speaking of 760 , I recommend the MSI Twin Frozr model.
It has great cooling and factory OCed.
Plus, it has great overclocking capabilities.
Benchmark from 2 websites proved it was almost on par with the 770 and even beat the 770 on one benchmark.
-http://www.bit-tech.net/hardware/2013/07/04/msi-geforce-gtx-760-twin-frozr-oc-2gb-revie/9
-http://www.techpowerup.com/reviews/MSI/GeForce_GTX_760_TF_Gaming/30.html