Random Read & Write Patterns
Now we’ll see the dependence between the drives’ performance in random read and write modes on the size of the data block size. We will only discuss the processing of small data blocks measured in operations per second. With large data blocks, the performance depends on the drive’s sequential speeds.
There are no surprises when the drives are reading in small data blocks. The standings are the same as in the response time test.
Seagate’s HDDs gain the upper hand as the data chunk grows bigger because they have a higher sequential speed which affects the result of this test at 8MB and larger blocks.
Judging by the results of writing in small data blocks, new things are not always better. The WD Caviar Black wins the test with an impressive lead. Second place goes to the 1TB WD Caviar Green that beats all of Seagate’s drives despite their higher spindle rotation speed. The Barracuda 7200.12 is actually the only Seagate product to be competitive to the 2TB drive from WD. The Barracuda 7200.11 series have problems have: the 1TB model is just very slow at writing whereas the 1.5TB cannot cope with 2KB or smaller data blocks.
Take note that the Seagate Barracuda 7200.11 is much slower than the others until 2MB data blocks. Its high speed of sequential operations helps it thereafter, though.