I always have 60-80fps in Minecraft, which shader could run at 40-60fps?
I say it the way it is:
If you have ONLY 60-80 FPS in VANILLA Minecraft, you will definitely not get stable 50-60 FPS with Shader.
All right!
There are a few lagless shaders with which you might have 30-40, but it depends a lot on your graphics card
I also have around 60FPS in the Vanilla, but I don't get 20 FPS with the smallest undemanding shader. You can completely forget 40-60.