Big Sur update causing havoc with FCPX & Apple Motion

Hello community,

After a night on the phone to Support and trawling through Forums I'm coming up blank and reaching out to see if anyone is having similar issues or found success with some workarounds.

I thought Automatic Updates had been switched off, but turns out they weren't which means my OS and software has now all updated for the latest versions. Since the upgrades, normal activity in both FCPX and Motion have becoming increasingly (and painfully slow). Simple things like moving through the timeline in Motion in a 4K project (with no emitters or generators) is difficult, and the timeline is unable to play at normal speed. With 1 second of footage taking approximately 4-5 seconds to play-out in real time.

Similarly in FCPX, background render which I can normally leave on during a project is also experiencing significant increase in time required. Working in a 4K project with two simple native titles brought rendering to its knees. This was with no colour correction, adjustment layers, key framing etc.

The computer was maxed out when bought 3 months ago (specs below) and has been handling magnificently until the recent update. Suggestions on other forums included re-installing 3rd party plugins, deleting preferences, creating a new user on the machine - I have done all of these with no impact on results.

Apple Support conversations are ongoing so I will update on this thread if any progress is made, but wanted to see if anyone else is feeling the Big Sur pinch?

Thanks, Robbie

\\ Computer Specs

macOS Big Sur V11.0.1

iMac Retina 5k, 27" 2020

Proc: 3.6Ghz 10-Core Intel Core i9

Memory: 40 GB 2133 MHz DDR4

1 TB SSD (820 Gb Available)

Graphics: AMD Radeon Pro 5700 XT 16GB

\\ Software

Apple Motion V5.5

FCPX V10.5