Performance degradation on Netbackup 7.5.0.7

Hi guys.

I am going crazy over this, let´s see if someone can help.

Infrastructure is the following:

Master Server: windows 2008 r2

Backup media: Data Domain

Backup type: VMware

So, here is the thing. VMWare backups going to data domain, at some point start losing performance, and I end up with backups running at 1mbps.

Solution so far, reboot the server, performance gets back to normal.

I have tried to find some article related to this but had no luck.

Last thing I did was enable shadow copy on the server.

Any ideas what could I look for?

BTW, this started happening probably after I upgraded to 7.5.0.7, I need to go to 7.6 but one of my servers is 32bits so I have to rebuild it on a 64bits one.

Thanks!