Ruigda 6442 max travel speeds

hi to all, wondering is any one was able to get high speed of ruida 64xx controllers
im trying to push engraving speed past 800mm/sec but looks like max im getting abound 300mm/sec max (physical) which is not enough for me. Leetro controllers i can push to 900mm/sec no problem.

i have servo motor that can handle 200/400 Khz signals (though dip switch goes beyond that for some reason, its programmable iVS servo)

even with ruida itself if i dont adjust step/turn value i can go mad fast but obviously at wrong travel distances, wehn i adjust steps my speed seams to be degraded to way lower then posted calues ex i set 100mm/sec about it looks like iit travels at least half slower.

I will make jig to measure exact travel speed so i don't have to guess.

anyone seeing same problems or any comments?