tested again, now on my ASTRO machine.
Changed there also the usbfs memory and run firecapture again. There is some improvement but still lots of errors, even without recording to disc. In 8 bit mode seems to be better (even when recording, only a few errors)
In 16 bit when recording, camera speeds jumps between 4fps and 29 fps with lots of errors 11.
Then I rebooted that same system in W10. Started firecapture with camera in the same usb port. Started in 16 bit mode ans started recording. Camera speed stays steady around 29 fps. Even when starting browser and browse internet or do something else. (On Linux, when I touch any other ap, I can see errors coming when reading the camera)
Very strange, starting to loose my confidence in Linux ...
The processor on that machine (AMD Ryzen3-1200) is not the fastest, but cam works in W10 like a charm. (And even on my I7-4790K it is not completely without those errors) Do you have any experience how it works on Mac? (Don't have a Mac to experiment