Why does Optifine crash?

Whenever I try to use a different shader or display shaders, my Minecraft stops responding = (

Can someone help me?

I have a really good pc and everything went great before that.

Here is my pc data

I7-4770 quadcore 3.4 Gh

16 Gb RAM

Radeon rog rx 570 8gb vram

Easy. Waiting.
Nothing will click while the shader is being changed. Can take 30sec. Depending on the system. If you click during this, it appears to have crashed, but it is not normally.

Well then comes the message that there's no response after waiting 2 minutes but thanks anyway

It is strange.
How much memory have you allocated to Minecraft?

8gb