robocopy /z is slower than normal copy

Copying files in restartable mode is much slower (about 6x over a network) than in normal or backup mode due to the necessary management overhead ______________________________________________________________ When copying with /Z, Robocopy reads and sends 64KB in each loop. When copying without /Z, Robocopy reads and sends 1MB in each loop. This makes a significant difference when determining values for /IPG. For example, rate-limiting a 100Mb/s line to 1Mb/s requires an /IPG value of 4