Yeah, that doesn't sound right. I'll assume you have 8 GB or more of RAM. You can press HOME in the title screen to enable DEBUG mode, which displays an FPS counter in the top-left once you're in-game (if it doesn't show up, press and hold J).
So I did some research, and it seems like this is a dumb GameMaker engine-side issue, but luckily there's a PC-side fix:
https://forum.yoyogames.com/index.php?threads/solved-game-not-running-at-60-fps-...