MSL Question

I dont know is it the true place to post this thread, however today i bought new mouse " it is secret whitch one" .. and i found in the disk with drivers one opitons Speed limit (+ x Hz/ - y Hz) is that MSL and is it forbidden? becouse when i make my Hz on 500+ my strafes are bliantly good whit a lot of sync and speed and when i decrease it 300- ... my strafes go fucked up ... Sorry for my bad english , pls help , becouse i jumped 254 today , :D and my last record with my last mouse was 252 ( exactly 1-2 day ago ) , is it from mouse or command SPEED LIMIT?