Results
RPI3
I think a 64bit image created for the RPI4 should work on the RPI3.
However, when trying the latest 6.3 kernel I compiled it just bombed on bootup.
So this is something I'll need to check at a later point in time.
Hard Disk
So far I've tried with and without the USB Hard disk but with no difference in results.
I think it's safe to boot from a USB Hard disk, at least with the RPI4.
TODO
- re-write the latency test script in python
- test without glxgears / xorg at the cli
- try Armbian
- http://linuxcnc.org/docs/2.9/html/
- Check the speed is 1.8Ghz
- https://www.raspberrypi.com/news/bullseye-bonus-1-8ghz-raspberry-pi-4/