Extreme Optimization!

* You can disable redstone light in Universal Tweaks to increase performance!

Enable threaded chunk rendering

Some third-party launchers are unable to install older versions of Forge (or they will ask you to install Java 8), you can use 1.12.2 Forge Vanilla Launcher 3.0.

!Optifine may not work in this modpack, but you can try adding it yourself.

Highly recommend these mods, not added to the modpack, because they do not correspond to the concept of extreme optimization (or other reasons) and "Base", but may be more useful than others QoL mods:

Nothirium - Changes Minecraft's chunk rendering engine to use modern OpenGL which greatly increases performance. Similar to Sodium but this is not a port of Sodium. (CensoredASM (in this modpack): Make sure that 'onDemandAnimatedTextures' is disabled in the CensoredASM/LoliASM config).

Get It Together, Drops! - Сan significantly improve performance in areas with lots of dropped items.

Surge - Aims to improve the load time and performance of the game.

Let Me Despawn - Improves performance by tweaking mob despawn rules.

Raw Input - Can make mouse input feel smoother and fix mouse jittering.

Fix Experience Bug - When players travel to and from other modded dimensions, there is a bug in minecraft where their experience is displayed as zero until they earn one new experience point or log out of the game and log back in.

TexFix - After everything is loaded it goes over your texture manager and deletes all the none animate sprites from your ram to reduce the amount of Ram that is using.

JEI - Item and recipe viewing mod for Minecraft, built from the ground up for stability and performance.

(Not necessarily, but can help with some errors):

Phosphor Crash Fix - Simple coremod that fixes the crashes caused by Phosphor's outdated injection annotations when using versions of mixin newer than 0.7.x.

* "Dependencies" shows only 90% of the mods in the modpack.