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.

Judging by the read response times, the previous-generation 7200rpm 2.5-inch drives are still competitive. They win this test, actually. They are followed by the new 2.5-inchers (the Scorpio Black is half a second faster than the Momentus 7200.3). The 3.5-inch HDDs are on the losing side. Yes, the small diameter of the platters and the shorter movements of the heads ensure a considerable advantage for 2.5-inch drives in response time. The 5400rpm 2.5-inch model is ahead of the 3.5-inchers, too.

The write response time depends on the efficiency of deferred writing algorithms. The 2.5-inch drives from Western Digital have the best write response but the 3.5-inchers seem to have the most efficient algorithms (you can estimate it by the ratio of write to read response). Seagate’s 2.5-inchers from any generation are far from brilliant from this aspect: their write response is higher than that of the other HDDs while their read response is just normal.