I have a 2019 Mac Pro tower with a 5K monitor that can't run Premiere. Stuttering and lag is soup du jour, every day. Why, you ask? You'll have to inquire with Adobe who saw fit to spend months changing the media export window but couldn't lift a finger to fix basic performance problems on professional machines. Anyway, this was a bug that I filed years ago that still hasn't been fixed, but if you want to "fix" it yourself, hit Get Info on Premiere Pro.app and check the box "Open in Low Resolution" It'll look like 2005, but at least it'll finally run like a $600/year program should. The difference is night and day!
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