I still think that an i7-4790k would be better for gaming than the i7-5820k in my opinion and cheaper because of the cheaper motherboards and cheaper RAM. I saw a review that showed the 4790k beating the 5820k in gaming benchmarks that were CPU bound otherwise there was not much difference, but in the heavily threaded benchmarks showed the 5820k beating the 4790k. Besides, with that logic you are using about no performance loss at 1080p with SLI, I can say that you are not really losing performance in gaming going with a quad core CPU instead of a hex core CPU, especially if the quad core CPU is clocked much higher by default.