video-sync-max-factor=1 allows better video sync on slow machines?

[Trinity3e]

I am putting a slow machine (embedded cpu) play 4k vp9 video, without gpu acceleration, it drops about 10% of the frames but otherwise plays well.
With the default config, the video will start to lag behind the audio within 30 seonds or so.
I firstly tried different video sync and drop settings with no change, if anything it made issues worse such as video freezing as it's trying to sync.
Then i found video-sync-max-factor. If set to 1, with no other changes to config, the video and audio are mostly in sync and playable.
For me this works fine in every situation, even with videos without frame drops. If it doesn't affect anything else, I suggest adding this to the fast profile.

[llyyr]

That option has no effect with video-sync=audio, so you're experiencing placebo effect.