studio using cpu at rendering when i haven't select it!

Hello all....last version of daz studio with a 1080 ti and a 970 clicked to used at viewport and rendering....still....when im rendering something i see 100% cpu usage (i7 12 cores) which slows down everyhting....
any idea why this is happening?
Comments
If you check the log file (Help>Troubleshooting>View Log) after rendering it should have a list of what component contributed how much to the render.
Thanks Richard...will do that!