To wind up this section of the review, the following diagrams will show you the Database graphs of each of the four new drives at five different queue depths.

We know that a larger angle of inclination of the graph indicates a higher efficiency of deferred writing, especially for short queue depths: the drive’s performance is increasing as there are more writes to be performed. Seagate’s Momentus 5400.4 drive is far from efficient. The angle of inclination of its graph is small even at a queue depth of 1 request. Its NCQ algorithms do not show up much, either. Thus, this HDD prefers to execute requests for data just as they are, without any optimizations.

The 46 series drive from Toshiba is not very efficient in terms of deferred writing, either. NCQ works here, but in an odd manner: look-ahead reading can be observed at a queue depth of 4 requests whereas request reordering is only noticeable at very high loads.

Besides higher-density platters, the 52 series from Toshiba has acquired new firmware. Take note that the efficiency of both deferred writing and NCQ algorithms has improved greatly. The effect of these features is now more conspicuous at low loads.

The new 320GB drive from Western Digital is good in terms of both deferred writing and NCQ. It delivers a remarkably high performance at high loads when there is a low percentage of writes. This is indeed an excellent result for this class of HDDs.

And here are the diagrams for the other tested HDDs:

• IOMeter: Database results, Fujitsu MHY2 BH, 250GB
• IOMeter: Database results, Hitachi Travelstar 5K250, 250GB
• IOMeter: Database results, Samsung M5S, 250GB
• IOMeter: Database results, Western Digital Scorpio, 250GB