I have troubles getting my motors running above 400 mm/minute.
I have modified my 5XC board to run full steps in order to get the steps/mm down to 320.
Whenever I try to run at higher speeds than 300 - 400 steps/mm my motors start rotating while accelerating, then stalls when speed gets above 400steps/mm and make a high pitched sound while running at the desired speed, finally the motor starts rotating again when the stepper driver decelerates.
To me it seems wierd that the speed is THAT low, but then again i am new in 3D printing.
Does anyone have some clues to get the speed up?