this thing is so dang buggy. might have to buy another xim 4 
I'd wager it is likely operator error over equipment failure...
Troubleshoot it starting at the simplest point.
fair enough. i swapped out my dead xim 4 for the apex. all other things equal. had no issues with sensitivity spikes previously.
It works most of the time just fine but i get those random sensitivity spikes that I can't attribute to anything other than Xim Link software. Mouse accel is off in the logitech software, no hotkeys for temporary dpi boosts or accel boosts and windows mouse accel is off (enhanced pointer prec).