The display in gig performer or that value shown in activity monitor of the OS?
If you are referring to the CPU meter that is displayed at the top right of GP, then that’s negligible and it means that something else is misconfigured.
It should be rather obvious that many thousands of GP users wouldn’t be using GP if it clicked all the time. It should also be obvious that the Cherry Audio people would not have included this special version with their plugins if it didn’t work with their plugins.
Clearly something is wrong but please don’t assume blindly that it must be Gig Performer.
Based on experience, the culprit is very rarely GP. In my case, it is usually user error, hah!
What do you mean by run several plugins? Do you mean having them play MIDI recorded in tracks?