Denis:

SCSI vs SATA makes a big difference. SCSI would give a significant performance enhancement.

When I did the testing I had Symantic Endpoint (aka Norton Corporate) AntiVirus fully turned on. The trick with any AntiVirus software is to make sure it is not checking the following folders;

Data
QRASP
Softrak

I've also found the retail and/or OEM version of most antivirus programs to be a problem.