Asrock Q1900M: Unexpected Realtime Delay, but Good Latency Values

So i bought a Asrock Q1900M to replace a failing c2d machine, since i have this board in a nas and it gets good latency values.

Unfortionatly despite the good values, see attachment, running linuxcnc gets an instant Realtime Delay error. I am running a 45us base period and a 1ms servo period.

The test below was run with some glxgears 2 dd's for io and a wget to load network. I cant seam to repoduce any latency excursions with the latency tests.

Any ideas?

the J1900 dosent have hyperthreading, nor dose the board have tpm, i disabled all the low power c states, onboard audio, the igpu (machine is headless).

If i could somehow repoduce the latency excursion in latency-test/ or the histogram that would be great, but i cant get it to happen.

latency-plot is really just a different way to query the same information, and it looks great too.
The problem being that all the tools see ~4us jitter max no matter what i do but linuxcnc itself fails instantly.

I dont think headless is any problem, the previous old c2d machine was run headless too.

Yeah Instantly anytime linuxcnc is run.

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