Its faster because it only scans to see if you have updates installed that are in ITS database. It doesnt compare your system to the update specs to see if your system requires it, and as such, can install updates you dont need and can break your system since certain updates are only designed for certain configurations. Only microsoft's checker properly checks to see if your system meets specific pre-reqs for certain updates. Windiz, on the other hand, just bulk installs and scans for any and ALL updates.