I've been running 1.10c "CTHON_NONFORCED" most of the time, but my first version 1.07 also doesn't work like it used to. I tried 1.11 just now, but it seems to be same performance wise. I noticed when playing with fraps (not recording) that frame rate was 26-27, and in some areas it dipped to 21-22 for a while before returning to 26. But since I didn't check what the frame rate was when the game worked normally, I don't know if these frame rates are normal or not.
The previous version also dropped in performance? That is super weird. Here's what I would try first: delete the version you've been working with, perform a restart, and then download the latest version and give it another try. If its impacting previous versions there is either something not right with your machine or there might be a memory leak somewhere that I need to hunt down. I have reached out to the Game Maker community as well to see if anyone can shed light on the issue.
Yes, 21-27 FPS is not normal. It should be running at close to 60, ideally. On lower end machines I normally see it run between 55-60 FPS.
This is strange. I restarted my computer, and right now the game runs smooth. I didn't do anything right before the restart, but I've had my computer on for quite a long time, and during that time I uninstalled some codec pack (klcp or something) and some kodi player, along with nvidia gaming experience software. I had the gaming experience before (so I doubt that's the reason), but the reason I uninstalled kodi + some codec pack is because my game started running slower a little after I installed those stuff on my machine, as before them it was running smooth. It could be a coincidence, and maybe have more to do with something else.