Jumpy downscaled 4k playback

Having issues in Beta for M1 mac with jumpy/stuttering playback of 4k footage on a 1080 timeline. Strangely this has not been an issue for me in the X86 version running through rosetta. The only apps other than premiere that are open are Safari, Mail, and Messages. Have also not had any issues running Photoshop and Premiere simultaneously when running X86 version, so I'm a little confused when it comes to the playback issue in Beta when Premiere is the only heavy lifting app running.