Playback slow and freezing up but video seems to be rendering fine

Playback is slow and freezing up, but when I scrub through the video it loads just fine, with audio and everything. It tends to be worse when I import a new video or change something like the scale of the video. I'm convinced that it's not my computer being slow because of how I can scrub through just fine, even faster than the playback speed. Is there anything else I can do to fix playback? I've checked things like GPU acc, playback resolution, and have high quality playback off,