The problem is only on UHD 4k videos, fullHD or HD no problems.
It looks like currently GPU load which require higher clock, but is not heavy and constant enough to keep the clock at specific level causes very big issues with DPC latency. Video is unplayable on my current graphic card
To workaround the issue one need to force full (higher) clock on GPU. Easily done by starting PCI-E render test in GPU-Z, which forces full clock on GPU core. This reduces dxgkrnl.sys latency , therefor fixing the playback issue.
Radeon Software Version