I just did some testing to figure out what was causing all the stutters and dips in fps, even crashes upon change of graphics settings or alt-tabbing, even though the CPU is not overloaded, the modpack is stable (even if big), the RAM is enough with an over-head available, and the GPU is not struggling a tiny bit. Then, it turns out, without texture compression, the game eats up the whole 12 gigs of VRAM. In comparison, with texture compression ON, it's twice as low.

Granted, on Windows, there is a way it handles the issue by using RAM for VRAM (as I understand), - while Linux does NOT do that, so the issues on Linux are much more visible. But that does not change the fact that it will still occasionally crash on Windows. The whole thing surprises me. Do all the people with big modpacks carry >16 gigs of VRAM? It wasn't common some years ago, 2022-2023, and even now it is not that accessible, unless you get the overpriced 4060 (ti) with 16 gigs.

From my limited testing, I saw no significant visual difference with the setting ON or OFF. The only thing that actually changed was the VRAM consumption being cut by at least 2 times.

TLDR; Why exactly must I not use compression?