Automatic stop with big jitter

I have a Dell GX270 and when I run the HAL Latency Test it reaches a max jitter of 17,000 which I can live with.
After several hours, however, it spikes to 75,000.
I have two questions regarding this:
1. If I set the configuration using the 17,000 jitter what will happen if the 75,000 occurs. Will LinuxCNC stop or will it result in sporadic movement of the axes?
2. Does anyone have any suggestions as to what might cause this? I thought it might be SMIs but from what I have read it appears that they occur regularly every minute or so.
Thanks, Jim

Power management (clock speed or core voltage changing, fan speed etc)
can cause random large latency spikes. I would make sure all power management
options are disabled in the BIOS setup.

A large latency spike might cause a following error depending
on the following error settings (and a following error will cause a fault and all motion to stop)
but normally a real time error will just result in a a warning