UE5 is intended to on all cores Visual Studio 2019 will build using all my 12 cores. When packaging the project for Windows 10 and cooking the content. Then often my 16GB is not enough. UE50EA needs 1.5 GB memory for each thread. UE5 auto tunes to get the performance on UE4 4 core build took 80 minutes now with UE5 and 12 core its under 20 minutes. Basically you cannot use the PC whilst building the shaders, but everything runs in the background.
I have increased my Windows 10 page file /system file to 16GB in Advanced Control Panel to fix the compiler out of heap errors if that is any use to you