I loaded up one of my busier patches, and when running it took up around 97-99% CPU. At one time it spiked to 100.1% - I’m not sure how that happens.
I paused it in the Engine menu, and it dropped down to 50-52%.
Then I un-paused it and then went around disabling all of the modules, even the blank panels. It was still up to 90-92% CPU. That surprised me very much.
Finally, I opened a new patch with the standard template (plus an LFO and five simple utility modules). That took up 29% CPU.
FWIW, System Report says this about my system:
||Quad-Core Intel Core i5
|Number of Processors:
|Total Number of Cores:
|L2 Cache (per Core):