The performance is better than modern versions because 1.12.2 lacks the heavy "blending" updates of recent releases. You can push render distance to 20 chunks with shaders on hardware that would choke on 1.19.
If using the CurseForge App , you can manage these profiles directly through their interface. Common Issues minecraft 1.12 2 shaders
Minecraft 1.12.2 shaders offer a fresh new lease on life for this beloved game. With stunning lighting effects, realistic water and reflections, and dynamic weather and sky effects, shaders can elevate the Minecraft experience to new heights. While there may be some performance impact and compatibility issues, the benefits far outweigh the drawbacks. If you're looking to spice up your Minecraft experience, give shaders a try – you won't be disappointed! The performance is better than modern versions because 1
In OptiFine Video Settings > Quality . Turn "Terrain Animations" OFF. This specific setting in 1.12.2 causes massive stuttering when loading new chunks with shaders enabled. Common Issues Minecraft 1