What is the difference between running the gp update (Microsoft) and ppupdate (PolicyPak) commands?

The gpupdate command updates all of the GPO's that are applied to the computer that is issuing the command. The ppupdate command only updates Netwrix PolicyPak settings that are contained within a GPO.

In addition, a computer must be online in order to execute the gpupdate command while ppupdate will execute if the client computer is online or offline.