SCSI HBA Card Problems

I am running an HP Proliant DL380 G4 server with an HP U320 64bit Single Channel SCSI G2 Host Bus Adapter. I am connected to five HP StorageWorks Ultrium 960 Tape Drives. I am getting a throughput of 240MB/s. When I plug the tape drives, using the same cables and termination, to the integrated 6i RAID controller I am averaging 500-600MB/s. The drive and HBA card are allegedly compatible according to HP.com. I am getting the following warnings using the HP Library and Tape Tools utility:

|__ Device Analysis : Passed with Warnings
||__ version: V23.07.2007
||__ Firmware rev G64D is up-to-date for Ultrium 3-SCSI as of Fri Apr 20 19:00:00 2007.
||__ Rule 19:
||__ The current SCSI configuration is likely to be limiting the performance of the drive.
||__ Please check that your HBA is the correct type for the drive and that the cabling is good.
||__ The SCSI configuration referenced is the one for which device analysis was run and/or the support ticket was pulled.
||__ If this is not via your backup server then you may not have an issue.
||__ Current SCSI configuration: narrow Recommended: wide
||__ Current SCSI transfer rate limited to: n/a Recommended: 320 MB/sec. or better
||__ The drives hardware compression algorithm is currently switched off.
||__ This was probably set by the backup software.
||__ The drive's setup has not been altered.
||__ There were 19 rules checked.
||__ Device Analysis completed, and warnings have been reported.

Has anyone else experienced anything like this? I have contacted HP but I am exploring other support avenues since it is taking them so long to work with me.