or maybe haven't reach the next step clock speed?

oh, i mean the clock speed not continuous one.
it increase by step.

let say a stock 600mhz core clock, with 30mhz step.
when set the bar to 610mhz and apply, it won't overclock to 610mhz, it still stay at 600mhz.
when set the bar to 620mhz and apply, it probably overclock to 630mhz or still stay on 600mhz.
when set the bar to 630mhz and apply, it will overclock to 630mhz.

so this is what i mean la.