Disk Response Time
In this test IOMeter is sending a stream of requests to read and write 512-byte data blocks with a request queue of 1 for 10 minutes. The total number of requests processed by the HDD is over 60 thousand, so we get a sustained response time that doesn’t depend on the HDD’s buffer size.
Theoretically, platters with a smaller diameter should ensure a better response time than that of 3.5-inch HDDs because the angle of movement of the heads is smaller. But practically, this rule is only true for high-speed server HDDs. The noise from quickly moving heads would be too high to please a notebook user. The heads actuator would have to be made more robust, i.e. massive, which would be hard to achieve within a 9.5mm thick enclosure. Thus, compact HDDs are somewhat inferior to their 5400rpm 3.5-inch counterparts in terms of response time.
The HDD from Western Digital is obviously the best in this test. It is 1.5 milliseconds faster than the closest 5400rpm pursuer at reading and even ahead of the Seagate 7200.4, which is quite a shame for the latter.
The same WD drive boasts very effective deferred writing that leads to a low write response time. The Seagate 5400.6 and the Fujitsu have a good response time at writing, too. The Seagate 7200.4 is no good again (but it is good that its response time at writing is not higher than at reading as it used to be with Seagate’s drives before).