Performance Issues with MacPro Xeon 12 cores

Hi

As can be seen in the attached image,
there’s a big gap between Cubase Performance Meter and the OSX Activity Monitor info.
I suspect it’s an issue related to Cubase utilization of the ProMac multi cores.

The project is truly pretty loaded,
However while Cubase sees the available processor resources as almost gone,
and behave accordingly - Huge latency, slow GUI responses, CPU peaks which cause glitches, etc.

While this, on the other hand, the real processor load, as seen by OSX Activity Monitor,
is much lower.

Could be that this machine is not utilized effectively via Cubase?
It seems as the cores are not well used, and the load isn’t spread among the cores effectively.

BTW it’s exactly the same over Cubase 9 as well.

Any suggestions?

Thanks!
Booli.
Cubase Performance Enigma.jpg