Our first screenshot is the Hitachi drive with Automatic Acoustic Management (AAM) and Native Command Queuing (NCQ) turned on in RAID 0 operation with the second screenshot showing the same configuration with a single drive. The RAID 0 setup shows a 98% increase in the minimum transfer rate and a 41% increase in the average sustained transfer rate. The maximum transfer rate also increases 41% although the burst rate is slightly lower. We believe HD Tune has a bug as the RAID 0 results indicate access times improving slightly when in reality they should not change or perhaps even increase slightly. Our HD Tach results bear this out so we will ignore the reported improvements in RAID 0 access times with this program.
The third screenshot is the RAID 0 results with AAM off and NCQ on. The transfer rates are basically the same with the only difference being a further reduction in access times compared to our first RAID 0 test result. We noticed the same drop in access times when turning off AAM during our single drive testing in the first article. Although the access times are improved we believe the benefits in the acoustics department outweigh the slight performance improvements we noticed in our application tests. We found that enabling AAM usually did not alter the test results more than 1% and at times the scores were a tie.
Hard Disk Performance: HD Tach 3.0
We are also including HD Tach results for review. Once again the order of the screenshots is the same as in our HDTune results. In this benchmark we see a 50% increase in the average read rates and a 52% increase in burst speeds over the single drive configuration with access times remaining the same in the AAM on /NCQ on tests. Our RAID 0 results with AAM off show an improvement in access times and sustained transfer rates while burst rates decline slightly compared to our other RAID 0 test results. While these numbers are impressive, we will have to see if they translate directly to improved application scores.