i7-6700K vs i5-6600K Multiple GPU performance

[GPUEnthusiast]

It's pretty apparent that the differences between the i5-6600K and i7-6700K in single GPU performance for gaming are negligible, based on the testing done by Anandtech and DigitalFoundry in real time, even including CPU intensive games like Grand Theft Auto V and Crysis 3.

However, I have yet to see actual benchmarks for the dual GPU performance of each. All that I usually read is "expect noticeably higher multi GPU performance on the i7-6700K"

That doesn't help me because that is basically anecdotal at that point. I've googled around extensively to no avail. If somebody can even just find me a benchmark of a few titles with an i5-6600K and i7-6700K and the GPU being like an R9 295x2, that would be greatly appreciated.

This is for a very important streaming build for a friend that is around 2500 dollars. However, a good portion of that money is used on peripherals like dual 144 hz monitors, a nice case, AIO liquid cooler, 32GB of RAM, SSD boot drive and for scratch space.

As somebody still on an i5-3570K, I know how powerful they are, but I also want to make sure that he can upgrade comfortably to a second GTX 980 without completely bottlenecking the hell out of it.

Here are the options we can go with:
i5-6600K with 32GB of RAM, NZXT Kraken X61, and MSI Z170A Gaming M7
i7-6700K with 32GB of RAM, NZXT Kraken X61, and MSI Z170A Gaming M5
i7-5820K with 32GB of RAM, NZXT Kraken X61, and ASRock X99X Fatal1ty

I would like to know the best CPU and how tangible the benefits will be for gaming with dual graphics cards. I know right now that in the US, the 5820k is cheaper than the 6700K, but the boards are much more expensive usually. So the i7-6700K and 5820K about balance out price wise.

 

[Kryptkeeper]

more threads would be preferable espescially if streaming aswell so i wouldn't even consider the i5 for this system. Also i haven't seen a good comparrison of sli with skylake. I just looked up a haswell comparrison 4690k vs 4790k with 2 980s and there was definitely a difference. I don't know how the differences in the skylake architecture would effect performance.

https://www.youtube.com/watch?v=pDmuv8Q45iY

5820k would probably be the best choice. gaming performance will vary between 5820k and 6700k depending on how well they support multithreading, but with streaming and/or recording programs running in the background i would expect 5820k to pull ahead. also it supports 28pcie lanes and quad channel ram as opposed to the 6700k's 16pcie lanes and dual channel ram.

 

[GPUEnthusiast]

Yeah. That's what I was leaning towards. I'm just going to go with the 5820K, sure the i7-6700K is faster for gaming with single GPU, but I think the 6 core/12 threads on the 5820K will be much more conducive to streaming and multi GPU gaming. It also seems to have better disk write/read and RAM performance versus Skylake.