Apparently the issue is MV is designed terribly and the creator of this game either torrented MV or is to lazy to update their version cause RPGMaker's creator fixed the issue already. Anyways, the issue is the games play speed is synced to the framerate and when the framerate dips below 60fps, the game starts losing play speed so if the frame rate drops to 30fps, the game's speed itself is halfed. there has been a fix for this for over a year by a 3rd party and the creator patched RPG Maker MV not too long ago. I love that the game is a higher resolution than VX ACE but it sucks that there was the cost of MV being shit when the started.
Edit: you can turn the framerate/gameplay speed sync off in the options menu. It helps alot but it will stutter occasionally. From what I've heard about MV is it's very similar to VX ACE in terms of designing with very few new features. I own VX ACE and have over 100 hours in it, never made a game cause I couldn't figure out what to do lol. I always start it up, start planning, never looked up a tutorial (finally did a week ago) and design stuff but couldn't figure out how to implement or save it. No intentions of make an Adult game with it, don't like games that use Stolen assets and not interested in coming up with awkward dialogue for scenes.