Recently, I started to have very long waits for shader compilation. The material graphs don’t update very quickly either. This was not previously a problem. I can resolve it by manually changing ShaderCompileWorker from low priority, but have to do this every time shaders start to compile. It will sometimes compile more quickly if I save a material while waiting. The program will sit with the same number of shaders to be compiled for minutes at a time, which was never an issue before.
I have noted this with both 4.9 and 4.10.