Windows Using Up 11.4GB Of RAM Randomly

After a while of being logged in (around an hour or so) Windows will start randomly using up RAM, up to 11.4 gigabytes. When I look in the Task Manager there's literally nothing that even COULD be using up that much RAM. On idle it will use up 5gb and even that is much much more than all of the applications are using in total. Any media players I might want to use on my computer completely go haywire after the 11.4gb. MPC-HC will skip frames constantly with the audio also skipping, VLC will play the audio but not the video whereas both of these would play perfectly well when I first signed in. Browser players (flash basically) work perfectly fine though. When I play a certain game and shut it down everything goes completely insane.

If I play another game the fps will constantly stutter between a full 60fps (which is also my screen limit) and 48 causing the character to seemingly teleport every step instead of fluid walking. My browser will also do a sort of stuttering (Firefox) when scrolling, instead of sliding down the page it will skip a portion but it won't stop scrolling so instead of the "tom's hardware" logo shifting down it will just skip it and skip the next part and the next etc. Though this issue does effect browser players, it doesn't effect application players (VLC, MPC-HC). Except only video players will stutter and everything else (browsers, games, regular applications) will work fine.

MPC-HC's audio will skip and fall behind the video causing basically for the characters to be mouthing words the audio played 5 seconds ago. VLC will start skipping the video while the audio stays intact so when a frame gets stuck it will just skip ahead to where the audio is. Any of these usually occur somewhere between 30min-1hr after being signed in. Once it does I have to shut the computer down and boot it back up again for everything to work normally again. Unfortunately I can't find anything specifically on this that's proved useful (installing/uninstalling certain windows updates as well as checking AV and drivers, uninstalling things).