Slow data stream on RedHat 5.8 with Netbackup 7.5.0.3

All,

I have a problem with a slow data stream when running a Netbackup Media Server 7.5.0.3 on RedHat 5.8. We are migrating systems from Solaris 10 to RedHat 5.8. The speed on Solaris 10 is about twice as fast as the RedHat 5.8 system. Also, we have no problem with earlier versions of RedHat, just 5.8. I was told that the 5.8 version is a different animal than even RedHat 5.6. Is there a different OS config I need to set up to get RedHat 5.8 and Netbackup 7.5 to get along? Possibly buffer changes, kernel tweaks, etc?

Thanks.