I just recently acquired an RX Vega 64 and installed the latest Crimson drivers (17.8.1).
It seems whenever I attempt to play any hardware accelerated video content via Flash or DXVA2. My system will shudder/freeze as if it getting flooded with CPU interrupters but my CPU utilization is only around 20-30% at most. The power states on RX Vega 64 for GPU/memory are going back and forth (both on set on auto). I'm wondering if anybody is experiencing similar issues. There's no issues with gaming though.
My system specs
2x4GiB G.Skill PC3-12800
Sapphire RX Vega 64
Corsair CX-750M PSU