To long story short,
-It seems that the issue is mostly OS related, not from hardware.
-The last macOS with working proper timing is Monterey (in 7th January, 2025. Timestamp matters, since Apple can patch someday).
All the tests are done with coder demo script ‘timeByFramesEx.py’.
In macOS Sonoma, miserable frame drop, and binomal distribution of frame & flip intervals.
Then multi-boot tested with AsahiUbuntu, Since AsahiLinux(Fedora based) requres a lot of package compile to install latest PsychoPy. without docker.
The difference is amazing. Now looks like usual 60Hz Display. However, the AsahiUbuntu seems a bit unstable. random framedrop happens and the number of dropped frames are hugely vary. below is the worst result.
Since many postings reported that frame issue arised after Ventura upgrade, I downgraded M1 macmini to Monterey.
Now, still not very satisfying, but proper distribution.
I will re-run the test with proper 120Hz setting of EIZO FG2421 monitor when USB-C to dP cable arrived.
Roll-back to Monterey is not easy. It requires DFU restore, if you are in Sonoma or later.
