A single GTX 960 rendered just 21fps at 2560x1600 in Crysis 3, while adding a second using SLI technology boosted performance by 62% resulting in an average of 34fps. Ideally, we hope for scaling efficiency of at least 80%, so there could be some driver work to be done here. Still, this is better than the 49% boost the GTX 970s saw when using SLI.
The GTX 960 SLI cards were just 3% faster than a single GTX 970 and 11% slower than the GTX 980 along with being 6% faster than the R9 290 and 8% slower than the R9 290X. Compared to the R9 280X Crossfire cards, the GTX 980 SLI setup was 19% slower.
The GTX 960 managed just 38fps at 2560x1600 while adding a second GTX 960 resulted in a 76% frame rate boost. Now with 67fps, the GTX 960 SLI cards were 6% faster than a GTX 970 and 6% slower than the GTX 980. Despite delivering 29% more performance than the R9 290 and 20% more than the R9 290X, the GTX 960 SLI setup was still 20% slower than the R9 290Xs in Crossfire.