Whoever is writing these drivers is doing a terrible job. I've found the updated drivers add lag to the mouse, then I reverted back to the old ones, the mouse is more responsive and feels very light.
This isn't the first time this has happened. The Z77 Extreme4 had the same problem.
Why update the drivers if they're worse than the orginal drivers on the CD?
I'd complain to Asrock but they get the drivers from Intel.
I uninstalled the drivers and the bios shows the driver I uninstalled still in the BIOS.