My server has a total of ~38300 items so far, and when I search in the GUI it's extremely slow whenever I update the search box string (type new text/delete a character, etc.).

I have roughly browsed source and my guess is the search method in the current version is going through all item database with O(n) speed.

Perhaps build a tweaked suffix tree (for substring searching) after all items are loaded could speed up it.

I will close this issue. I will rework IGCM the next months and remove the crafting/ furnace configuration. Sorry, but it's way to hacky and causes many issues.