So I'm looking into a new computer and wanted to know if I should buy the Skylake Quad-Core or the Haswell-E Hexa-Core. I want to be able to stream games like ARK and H1Z1 without to much of cpu bottlenecking.
Honestly either or will suffice for what you have said.
6700k - Fastest QuadCore on the Market at this time, handles anything, rendering, workloads, and even some major workstation applications. Recommended with only 1 GPU, anymore will technically be a bottleneck itself since it doesn't support full 16x/16x and only supports 16x or 8x/8x
5820k - Cheapest X99 Chip you'll find on the market at this time, handles anything a 6700k can do, plus gives you the option to do Dual GPU in full 16x/16x which is using the full potential of both video cards, 8x/8x is using half of each, at half the bandwidth, so lower frames than 16x/16x. Overall, the more cores, and the better the processor, You'll have a better time with this one trust me.
Right now the 5820k is a tad bit cheaper than the 6700k, I'd recommend getting the 5820k because it has 6 cores and 12 threads which will come in handy with 2k, or 4k rendering video. For the Price to performance, The 6700k only beats it in single threaded applications mainly because of the stock clock speed, and having a tad bit newer architecture
Best Of Luck!
~Zac's Custom.