Servo Max Jitter bad without glxgears running.

Hi,

I am new to CNC and this forum. I am trying to set up my first machine and I have linucnc running on a gigabyte E3000N. When I do the Hal latency test I get over 125000 on the servo thread and less than 15000 on the base thread. I tried to turn off all things in bios and in the OS(the screen saver is bad). I also tried maxcpus and isolcpus etc. But then I saw that if I have glxgears running I get good results for Servo around 13000 and 10000 for base. Se pics. I made a video with latency-plot turning on and off glxgears.

I have a feeling this is due to some energy saving setting? When glxgear starts something wakes up.
or since I run in dual core maybe glxgears blocks one core? but I tried to run one core and It did not help. Hmm
Anyone had this problem? Any ideas?

For now I will just run with glxgears in the background.

With glxgears running. OK


No glxgears running. BAD


latency-plot


Thanks

That does sound like that is power management or perhaps caching related

Have you turned off _alll_ power management options in the BIOS?

(Cooll&Quiet etc etc)

Strange, it does that only for servo thread, base is unaffected !!!
Usually it is the opposite.
Never seen this happen.