I had simular symptoms on one of my computers after I updated the bios.
When I watched netflix or youtube while playing something, the Graphics could freeze for a short moment and I got sound distortion, like brrrrppph. Sometimes it could even BSOD.
The fix for me was to disable the intergrated graphics in bios. When I updated the bios it turned it on without me noticing. After I disabled internal GFX again, everything has been fine.
Does your cpu have integrated gfx? Is it on in bios?