1080p > 4K sequence Drastically improves GPU playback!?!
Slow timeline playback (Non-optimised GPU Mercury playback)
Converting 1080p sequence to 4k sequence (in project setting)
drastically improves playback of 1080p files!?!?! (and applying "Scale to Frame Size")
I suspect that Mercury GPU is badly optimised, and once i up-res the sequence setting to 4k, the GPU is better optimised.
Playback performance drastically improve (but playing reverse speed is still not smooth)
Premiere 2018 12.1.2
Rostislav Alexandrovich commented