The issue obviously is that NW recognizes a larger block size but your system 
prevents to read block sizes larger than 64kB. This is a known issue.

You must 
  - install a compatible SCSI driver.
  - ensure that the SCSI block sizes limits have been increased 
(scatter/gather).
  - If you use Windows 2003 SP1, you must also fix it because SP1 limits the 
required changes once again.

You will find more details in the NW 7.3 Performance Tuning Guide. Good luck.

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