Restores to an EMC clarion CX500 are very slow using netbackup version 6.0
or version 5.1.

However netbackup version 3.4 and 4.5 restores of the same data are fine.

All flat file restores.

Anyone explain why it should be slower on later versions of the software.
I am talking 4mb/s using 5.1 and 6.0 and 24 mb/s using 3.4 and 4.5