[Darryl Ramm]

What interface?
What session sample rate?
What IO buffer size?
What drive is the audio on? (You should be using the internal super fast SSD on this computer, disk issues can exacerbate CPU errors)

Make sure disk cache is enabled=set to a size
Ignore errors is off at least while troubleshooting
Dynamic plugin processing off

What troubleshooting have you done on this new system?
You should of at least already tried...
Trashing prefs
Testing with standard output as the playback engine
Removing all third party plugins
Testing starting with a new empty session
Testing from a newly created admin account
Disabling hyper-threading
Looking for possible denormalization issues (runaway/spiky CPU use of some plugins)