Steppers stuttering

Does it sttuter only when jogging or when running gcode ?
I could only try it during jogging. When I use a salt axis it goes very well "without jogging" but I move the 5 axes at the same time, there is much jogging. I have to stop the machine.

Do you get latency warnings? 888000
Did you measure the power supply voltage while motors are moving? No

First thing, try a different keyboard. I have a USB keyboard
And do not change the servo period, set it back to 1000000 ( 1 million), that messes everything if set to other values. I had put 100000 because my first configuration works very well with this value

Thank you

What does 888000 mean?
It does not matter if the keyboard is USB or PS/2, some have issues with "typematic rate" or rate of repeating when a button is held pressed. Try another one, or try this :
forum.linuxcnc.org/38-general-linuxcnc-q...elocity-fluctuations
Servo period must be 1 million, base period can be as low as you can set it without getting latency errors, so 100000 is OK for base period.

First thing, try a different keyboard. 
I have a USB keyboard
I put a keyboard & mouse with UBS wire but nothing changes, always stuttering.

And do not change the servo period, set it back to 1000000 ( 1 million), that messes everything if set to other values. 
I had put 100000 because my first configuration works very well with this value
I tried to put 1000000 in "base period" but it accentuated the stuttering ... it works much better when I put 120000. I have the same disturbances on my frequency converter, my spindle has speed variations...

Thank you
 

You are mixing base period and servo period,
base_period 120000 <<<< is OK, anything that works without latency warnings
-
servo_period 1000000 <<<< must be 1000000, can be changed but other values have to be changed accordingly.

Attach the hal and ini files so we can have a look.

Hello,
no, I do not confuse the best configuration I could find with this computer is well :
servo_period: 120000
base_perido: 59480.

if I put 1000000 the servo_period it works less well.
my "max jitter" varies between 15000 and 9900000

Thank

Hello, 
Can you see my files ? 
thank you