https://www.youtube.com/watch?v=rrFkrDoxjZo&feature=youtu.be
PS20 / PS21 Brush lag comparison with identical system and program settings! It is unusable. Finder latency, brush lag. What a crap! Any idea... It does not deal with brush smoothing (deactivated), it does not deal with GPU (iMac Pro with 120 GB memory and Vega Graphiccard) and it does not deal with cache, as both documents are opened just right before.
Test with identical brush strokes, color, transparency and speed. Such a mess...
PS 20
PS_test_22-a7287330-51f5-42d9-bf40-ff33b5d00359-1135654724.jpg
PS 21
PS_test_21-32142450-46be-4d15-8d71-03941971b7d5-1134731203.jpg