Laggy playback

Hi,
Running musescore 4 on a windows 10 machine with a core i7-7700k. More than enough cpu power. I was getting really laggy playback, so I opened up task manager while it was still running to see if some other process was running and eating a lot of power. It instantly got better just by having another application selected. Seems to only lag when the application is selected. Anyone know what’s going on?