As the title suggests, there has been a performance issue regarding block entities (most likely belts as me and my friend have made a massive factory), where loading create specific block entities causes a massive drop in FPS. For reference, i have a 2080 super graphics card, a i9 990k Intel CPU as well as 32 gigs of ram and my frames drop from 200+ fps to 40-50 fps. While i can play fine with these levels of FPS, my friend who has a far worse system than i do can barely play the modpack, yielding roughly 26-28 fps tops. This can very well be a Create specific issue but ill leave this ticket here as some other 3rd party mods may have affected the performance.

After some further investigation, my friend did a test in a creative world where a bunch of belts were placed. This is what he got:

This is what he got when he looks away from the belts: