Why is Premiere' PLAYBACK PERFORMANCE slow as fudge all of the sudden? Because it implemented a cool new feature that can actually be horrible on the wrong system (most systems?!?). Maybe they forgot to test with non-workstation GPUs or on low quality motherboards? If I knew for a fact that a non-cheap motherboard upgrade will make this work as intended - I think definitely yes. Let me know if you have any background info on this please!
Premiere Pro 2020 solution: https://www.youtube.com/watch?v=Jz1rb62wIh8