From my own tests (on my 2012 Macbook Pro 15" Retina with Catalina) setting the resolution to the highest possible 3840 x 2400 , BIAB is out of sync by probably 300 milliseconds. That said, everything in the OS is sluggish on this machine in that resolution, although playing a fullscreen Youtube video was fine because that uses GPU acceleration.

Changing the GPU from integrated to discrete didn't help, but changing back to the "Default for display" resolution (which is a scaled 1440 x 900 resolution, actual screen resolution is 2880 x 1800) eliminated the delay.

I can't run Big Sur on this Macbook, and the only Big Sur compatible computer available to me doesn't have a retina screen and doesn't lag on it's own, so I can't say whether this is any better or worse with Big Sur.

Last edited by Simon - PG Music; 01/21/21 01:03 PM.

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