Slow backup from media server

Hi,

We are running Netbackup 7.6.1 on Windows 2008 R2 Sp1.

We have 1 master and 6 media servers.

One of our media server is not backing up as fast as the others. We are usually able to backup at 70-90MBps even more, but on this one particular media server we are unable to get more than 20-30MBps.

Any idea why or what could cause the speed difference?

Thanks for the help.

Philip