I have noticed that the performance would go to hell when combined with other specific mods, testing out each one out individually I found that the game would run fine if the hack was disabled or if the hack was enabled and those mods disabled, but having both the mods and the hack at the same time would tank the game

after a bit of digging I found that the other mods in question were saving their data every frame, which I guess makes sense, a couple mods saving a bit of data every frame isn't too bad, a couple mods calling the hack and triggering it to save every mods data every frame is a bit more intensive

after modifying the mods to only save on new room or when certain values were updated the issue disappeared, so yeah, if anyone's getting terrible performance try to figure out which mods have the issue and check them for saving data too often

it should be up to the mod devs to fix their mods, but maybe a 'cooldown' for saving in the hack could help?

(I dont remember the specific mods but I did double-check by modifying one of my mods to save on post_render, with that change in and hack enabled the game ran at about half speed and that was just 1 mod)

Well for what I know, the Mod Compatibility Hack only doubles the lag from saving, so unless the mods were laggy on their own due to the constant saves, MCH would probably not cause any huge increase, just double. I may be wrong though, I'll notify the author.

@☢ Nato Potato ☢ Apparently the issue lies with MCH saving data of ALL mods whenever SaveData() is called, this is due to how it merges save files to preserve data between updates. As you might know MCH only has one Save.dat file like other mods, and as such merging all of the mods' savedata into one single file is the only way to do it.

The issue is, if you have a mod with an awful saving practice like that and Revelations installed, Revelations will be basically saving their data every frame as well. Which could cause really bad lag, yeah.

When I played Bertran with this mod enabled,it crashed the game. I think it's because the MC_PRE_PLAYER_COLLISION callback cannot be overridden on him. This could also include Samael,and others that may not have that callback be overridden by this mod while in a run.