OK - it was well worth a try!
So lets think about what else it is doing - it is talking to itself (NetBackup does that a lot!!) so you could add itself to its own Hosts file to rule out slow name resolution.
Next, it has a lot of stuff to update so you could keep the amount of things showing in the console to a minimum - adjust and remove columns that are not required and set the amount to be kept in the activity monitor to a minimum by adding registry setting under:
HKLM\Software\Veritas\netbackup\vurrentversion\config\
The default values for KEEP_JOBS_SUCCESSFUL_HOURS and KEEP_JOBS_HOURS is 78 hours so simply add these DWORD keys and use a decimal setting lower that that to change them - need a service re-start to take effect - or maybe they are already there and very large?
Then you can change the refresh rate - while in the activity monitor select View - Options. Most tabs have their own refresh rate.
Hope something here helps - start with the hosts file (include virtual and node IP addresses as you are in a cluster) as everything is TCPIP in NetBackup!