Performance in Intel IOMeter
Sequential Read & Write Patterns
IOMeter is sending a stream of read and write requests with a request queue depth of 4. The size of the requested data block is changed each minute so that we could see the dependence of the drive’s sequential read/write speed on the size of the data block. This test is indicative of the maximum speed the drive can achieve.
The numeric results can be viewed in tables by clocking the links below. We will be discussing graphs and diagrams.
It is only at sequential reading that the 2.5-inch drives differ: the Momentus XT is ahead of its opponents on small data blocks. The 3.5-inch drive from Seagate is unrivalled, though. The Toshiba is somewhat disappointing as it reaches its top speed on data blocks of 32 KB only.
The Momentus XT is better than its predecessor at sequential writing: the Momentus 7200.4 is somewhat better than the others on small data blocks but falls behind them on large data blocks.
Disk Response Time
For 10 minutes IOMeter is sending a stream of requests to read and write 512-byte data blocks with a request queue of 1. The total of requests processed by each HDD is much larger than its cache, so we get a sustained response time that doesn’t depend on the HDD’s buffer size.
The Momentus XT is somewhat worse than its opponents in terms of read response time. The HDDs are all close to each other in terms of write response time.
Take note how much better the 3.5-inch HDD is in comparison with its 2.5-inch counterparts. Yes, it has to move its heads by a larger angle, but its actuator is more powerful. Moreover, its server orientation allows it to move its heads as fast as possible, disregarding the noise factor.
Random Read & Write Patterns
Now we will see how the performance of the drives in random read and write modes depends on the size of the requested data block.
We will discuss the results in two ways. For small-size data chunks we will draw graphs showing the dependence of the amount of operations per second on the data chunk size. For large chunks we will compare performance basing on data-transfer rate in megabytes per second.
We don’t have any unexpected results at random reading. It is good that the Momentus XT doesn’t produce the odd-looking hump which you can see in its predecessor’s graph. The difference in performance is small while predictable results are far more important.
The two 2.5-inch drives from Seagate behave completely differently at random writing. The Momentus 7200.4 isn’t good at writing small data blocks as if it has too few cache lines to store a lot of small write requests. The Momentus XT is free from that downside. Moreover, it performs faster than its opponents on some data blocks, so we can suppose that its flash memory takes part in caching write requests. We can’t be sure about that after only one test, though.