Hmmm...
I'd probably go with RYZEN.
Yes, the 1080p FPS can be higher with Intel but here's some advantage for the R7-1700X
1) AM4 platform may be upgradeable later to an even better CPU (i.e. ZEN2 8-core)
2) AM4 platform should be around a long time, thus replacing the MOTHERBOARD after Warranty expires should be easy (Intel may be problematic)
3) Mores cores/threads for multi-tasking especially if you want quality, CPU-based encoding (not just NVENC hardware acceleration)
OTHER:
a) If Ryzen you should get 3000MHz/3200MHz DDR4 memory in Dual Channel (i.e. 2x8GB 3200MHz DDR4)
b) COFFEE LAKE is a better choice if going with Intel IMO (compare cores/threads, frequency and price of CPU's)
c) future games will begin to utilize the cores/threads more with DX12/Vulkan so at some point the R7-1700X becomes the better CPU and it should easily last 5+ years.
d) RYZEN will start to do better as the architecture is optimize for once games/applications are created with an optimized compiler
OTHER:
if going Ryzen, research the system memory (DDR4) compatibility with the chosen motherboard to ensure it hits at least 2933MHz. some confusion there