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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 a disk’s sequential read/write speed on the size of the data block. This test is indicative of the maximum speed a hard disk can achieve.

The numeric data can be viewed in tables (click the links below). We will be discussing graphs and diagrams.

The 7200RPM disks deliver the same top speed when reading large data blocks. When processing small blocks, the Seagate is superior whereas the Hitachi even falls behind the 5400RPM disk from WD. The latter shows us a difference between the controllers: the included HPT-RR620 is faster than the chipset’s controller when reading small data chunks.

The 7200RPM HDDs both behave in the same way at writing, the Seagate again enjoying an advantage with small data blocks. The WD performs differently with its two controllers. It is slower on the HPT controller, even in terms of the top speed.

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 Seagate wins this test, its good results being indicative of what you can expect from a modern HDD with multiple read/write heads. The Hitachi doesn’t move its heads around that fast. Its designers must have thought about its noisiness besides other factors. As a result, the 7200RPM Hitachi is inferior to the 5400RPM WD in terms of the read response time.

The WD disk now shows the same result irrespective of the controller. Take note that this HDD is handicapped when writing small data blocks (to write a 512-byte chunk of data, it has to read a 4KB block, modify those 512 bytes in it, and then write it back to the platter) but we don’t see anything like that with the Seagate. So, the Seagate drive either has no 4KB sectors or features some miraculous technological innovations.

Random Read & Write Patterns

Now we will see how the performance of the hard disks in random read and write modes depends on the size of the requested data block.

It’s all rather boring in this random read test. The HDDs do just as we could expect them to, basing on their read response results in the previous test.

There are some interesting facts at random writing. First, the WD confirms it really has 4KB sectors because its performance is low with data blocks smaller than 4 kilobytes. The Seagate is just as positive about having no such technology. Second, the Hitachi has an unusual performance hit with 256KB data blocks. This may be some unlucky coincidence or a defect in its data caching algorithms.

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