Bad youtube framerate but only with audio unmuted

On 11rc4 running nouveau 1060 6gb and ryzen 5 5600x. Youtube performance is completely acceptable with low CPU usage (~10%), until I unmute and the framerate of the video becomes awful and stuttery. CPU usage also increases then to around 20% for the firefox process. Not sure how or why something like this would happen, firefox has no trouble detecting and using the nouveau driver from looking in about:support.
/Leo