The underperformance in gaming was tracked down to software issues according to AMD. Namely:
- bugs in the Windows process scheduler (scheduling 2 threads on same core, and moving threads across CPU complexes which loses all L3 cache data since each CCX has its own cache)
- buggy BIOS accidentally disabling Boost or the High Performance mode (feature that lets the processor adjust voltage and clock every 1 ms instead of every 40 ms.)
- games containing Intel-optimized code
More info: http://wccftech.com/amd-ryzen-launch-aftermath-gaming-perfor...
Furthermore hardcore gamers usually play at 1440p or higher in which case there is no difference in perf between Intel or AMD, as demonstrated by the many benchmarks (because the GPU is always the bottleneck at such high resolutions.)