Upgrading from Ventura to Sequoia, Boinc app using 2 GPUs makes GUI and videos choppy

On my 2019 27” iMac with 128GB or ram and built-in Radeon RX580 and Blackmagic EGPU Vega 56, I was running 24/7 BOINC with einstein@home apps with no problems. Upgrading to Sequoia makes mouse curser and videos always choppy despite the GPUs running at 3-5 % only.
When I suspend Boinc app, it runs smooth.

I notified Apple

Any ideas ? 

Thank you