The gaming performance issue is purely down to the higher memory latencies that Ryzen is running with. Since launch, latencies have dropped from about 100ns down to about 65-70ns and the performance had improve accordingly. the poorer latiencies are directly related to the secondary memory timings that currently cannot be changed by the end user as they can be on an Intel platform. Intel kabylake/skylake machines have memory latency in the 45ns range.
Next month the new ageasa microcode will be released by AMD and it is supposed to open up the system to support a much wider range of memory frequencies, hopefully the memory timings will also be tightened up or, opened up to user adjustment fo a much greater improvement in memory latency times. Just a reminder that X99 also had the same sort of teething problems when it was released as well.