Asrock Q1900M: Unexpected Realtime Delay, but Good Latency Values

Yeah Instantly anytime linuxcnc is run.

I also just tested locally (not headless) and the result is the same.

Did you try from terminal? Is there any useful info there?

theres no usefull info in cmdline output.

I reimplemented latency-test directly into linuxcnc using the timedelta hal module and pyvcp.
And now i can see that the latency excursion occurs once exactly every 60 seconds but only while linuxcnc/axis itself is running never when only latency-test or any of the other latency testing programs are run.

linuxcnc just has to be running, it can be totaly idle and the excursion will occure.

Very strange and i dont know what to try from here

The problem with the latency tests is that they just test dispatch latency.
it's likely what you are seeing is some kind of resource contention.

That makes sense.

Do you have any idea on how i could maybe debug what its stalling at?

What version of Linux, LinuxCNC and kernel?
uname -a
?