Causes of poor gaming relative to CPU performance of Ryzen:
Windows is load-balancing across CCXes. This means that a thread is being moved around on the CPU - which is normal - so that a single core isn't used more than others. On Ryzen, that needs to happen ONLY within a CCX, otherwise you will incur a massive penalty when that thread no longer finds its data in the caches of the CCX.
SMT hurts single threaded performance due to shared structure. Ryzen statically partitions three structures to support SMT: Micro-op queue (dispatcher), Retirement queue, Store queue. This means that, with SMT enabled, these resources are cut, potentially, in HALF (mind you, these are just queues that impact throughput of a single thread).
Memory latency quirks still not worked out. Gaming can be quite sensitive to memory latency and bandwidth. These issues will be, most likely, remedied with BIOS updates.
[...]
What this all means is simple: once the Windows update has landed, BIOSes are patched up, and SMT is disabled, an 8-core Ryzen will likely be competitive with a quad i7 in gaming while blowing past it in multi-threaded. If all you do is game, then the 1700 may well become a very valid option that will work increasingly better in future games.