Dramatically increased export times for unknown reason

[rupert rucksack]

Hi there,

I have an M1 Ultra Mac studio 60 gig ram and was so impressed with the performance, even on Premiere (!)

I used to whizz through renders but suddenly on this 5K project with a mix of formats including R3D files the render times shot up to 2 and a half hours for a 9 minute film.

I also have 4K BRAW and Youtube clips uprezzed to 5K, lumetri effects, but normally it cranks through this kind of stuff.

Just before the change I:

Started using an old Wacom Intuos pro and installed the latest drivers - but uninstalled everything and the same result.

I did fiddle around with HLG colour profiles but then went back to default settings. I have to say I still don't understand all of these and need to watchn a tutorial or two.

I am currently rendering out the timeline before exporting and that is taking 33 minutes. Which on this machine is chunky.

Now exporting the rendered timeline, using rendered ProRes previews, its still 30 minutes.

CPU usage on the render is at 350%, average 11% and CPU Load 4.22, but usage is 800% % on the export, load 7.53 - with preview renders on.  GPU 40%.

One strange thing I did notice that even at 35 mbps the final file was about 6 gig. After I rendered then timeline it jumped down to 2 gig at the same frame rate....

Any ideas welcomed !

Thank you

Rupert

[rupert rucksack]

render CPU usage peaked at 1500% and 15.0 load...