Best to have several compilers working at a slow speed or one compiler working at an optimum rate?

I’ve noticed that my CPU skyrockets to 100% usage when compiling shaders, which wouldn’t inherently be an issue, but despite this the 3 compilers (according to Task Manager) are all taking up under 10% of the CPU (over 50% is taken up by the editor) and shader compilation is agonizingly slow. I was wondering if I should set the amount of compilers to just be 1, giving it a greater proportion of CPU usage, or if having several would still be slightly faster.