Unexpected latency issue

Exactly!
If you have a 4 core cpu.
For a two core cpu, =0 or =1
But if the cpu has hypethreading that can not be disabled in BIOS, try =1,3 for a two core cpu, or =1,3,5,7 for a 4 core cpu.

Where do you see people using laptops with LinuxCNC running machines????
Those are probably all my videos, i have 3 laptops that can run machines, one only for testing as it uses an USB to Ethernet adapter and still works for hours without dropping the link, on batteries. The best of those got the screen messed up when i left it at a clients site. Shame, as it ran the machine for over two months without ever dropping the link.

Ooops, should have added, the one not mentioned above is an old ACER, also runs machines for days on end, found and bought another one, same model, did not work, gave it to a friend for free. It had utterly useless latency.

Oh you meant in general using laptops to run machines, sorry it did not light a bulb at the time.
Yes, some do use laptops, some sell machines with laptops, most of those use "USB Mach3" controllers, very often those come here to ask how to replace that.
Back on topic, do some testing, use
latency-histogram --nobase --sbinsize 1000 --show
to test latency, if there are huge excursions in the millions, do not bother anymore, see if there is a way to get into BIOS, otherwise nothing helps.
If the latency remains stable even at 200000 or more with no excursions, there is still hope as the servo period can be longer without affecting machine functionality. Beware that messing with servo period messes up a lot of other things, mostly the PID loop, but more when we get there.

LucasWorx wrote:

Hmm, I wonder why the second one wouldn't work like the first: I'm stubborn.

Not the same BIOS version, could not find anything as it was over 10 years old, i think. Could not disable hyperthreading.