have you tried adjusting your in-game settings - detail, resolution, window?

have you tried upgrading drivers, especially for the card? Also try giving high priority to smb and your recording software, might help a little.

Is footage necessary to submit a Super Meat Boy run? I have an okish 106 but no footage (my computer can't handle it).

Yes, submitting to leaderboards requires video proof. The runs you see without videos on this leaderboard were grandfathered in from our old Google Doc leaderboard and had been verified by a moderator prior to the migration to speedrun.com.