pressing play loads a very small % of the scene to cache. maybe 5% of the strip. There’s got to be some better way of doing this. My work around is just scrubbing over the strip multiple times until it loads, because if I just press play, it will never get all the frames. ive got an rtx2060, 64gb ram, I don’t think my computer is the problem. The scene doesn’t really have too too much going on and I’m only talking about like 120 frames. Thank you for your time 
in the preview window go to you properties - view - select pre fetch frames.
Are you sure that that works? I tried clicking that button and it didn’t load the scene strip to cache. Just want to reiterate, I’m talking about a scene strip, not a strip of video per say. The way the “prefetch frames” button appears in Blender (right under the Proxy Render Size) makes me think that it’s talking about prefetching proxy files. However, scene strips can’t be turned into proxy files considering they’re not even rendered yet (correct me if I’m wrong).
Thank you for the reply. If you could test out what I’m talking about I would really appreciate it.
What I do is go in the timeline, click on the “Playback” menu, and in the “Sync” dropdown select “Play every frame”. Then, I play the scene strip and it caches every frame. Not ideal since it has lower performance than prefetch (maybe prefetch is multithreaded) and I can’t do anything else while it plays, but it gets the job done.
Most often, because it takes a while, I go in my operating system’s sound settings and disable sound for Blender so I can do something else without being bothered by Blender’s playback.
Make sure you set your frame range short enough and set your memory setting (User Prefs > System > Video Sequencer) high enough so that the playback doesn’t go into a loop where it has to “un-cache” frames in order to cache the next ones.
Note: Because prefetch is faster, I still recommend using it for other strip types. However, if a scene strip is contained in a metastrip, Blender may crash when trying to prefetch it, instead of just skipping it. So until now I’ve avoided grouping scene strips. This bug may have been fixed though.