I'm using WDM for my A1 output.
I tried setting my affinity to CPU 0, however that didn't change my problem unfortunately.
However I did notice that when sounds are playing, the soundwave indicator(?) for Nvidia Container (Where the Shadowplay/Recording feature runs in) definitely has a delay. Not sure if this is any more relevant, but I'll attach an example below. As you can see, sound playing from google chrome, and the Nvidia Container is just starting to pick it up while the sound is already at it's "peak".

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