Random Read & Write Patterns
Now we will check out the dependence between the drives’ performance in random read and write modes on the size of the processed 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 the SSDs’ performance basing on the data-transfer rate in megabytes per second.
- IOMeter: Random Read, operations per second
- IOMeter: Random Read, megabytes per second
- IOMeter: Random Write, operations per second
- IOMeter: Random Write, megabytes per second
Reading in small data blocks is consistent with the results of the read response time test you have seen above. We can only note one irregularity: the graph of the Kingston V+ series shows that this SSD is good enough with data blocks larger than 8 kilobytes but does not accelerate much with the smaller data blocks. Anyway, its performance is over 5 thousand operations per second, so that’s not a problem really.
The results of the SSDs with large data blocks resemble the standings in the sequential read test. The shape of the Kingston V+ drive’s graph is closer to the graphs of its junior cousins rather than of the opponents. Perhaps Kingston’s SSDs all share something in common.
Writing small chunks of data is the headache of all developers of multichannel controllers for SSDs. The Intel X25-M is beyond competition here. The Indilinx-based SSDs deliver consistent and good results irrespective of whether they have MLC or SLC flash memory inside.
The rest of the SSDs fail in this test, their performance being ridiculously low in comparison with the leaders and their graphs barely rising above the X-axis. You can learn from the results table that the Super Talent MasterDrive SX is faster than the Kingston models among which the V+ series is the only one to be comparable to HDDs in terms of random writing performance. The other two SSDs from Kingston are downright slow. And we can also note that the 128GB model from Kingston is two times as slow as its 64GB cousin with large data blocks but overtakes the latter with 512KB blocks and leaves it behind when processing even larger chunks of data. Perhaps the larger model accesses data in larger blocks, which results in this behavior.
There is some confusion in the ranks as the SSDs process even larger data blocks. The outsiders from the previous diagram are downright poor here, too, but the Kingston V+ series stands out among them as its speed is growing up proportionally to the data block size. The Indilinx-based SLC-memory drives are in the lead here with the exception of the OCZ Agility which tends to slow down when processing very large chunks of data.