Results: 4 KB Random Reads
We turn to Iometer as our synthetic metric of choice for testing 4 KB random performance. Technically, "random" translates to a consecutive access that occurs more than one sector away. On a mechanical hard disk, this can lead to significant latencies that hammer performance. Spinning media simply handles sequential accesses much better than random ones, since the heads don't have to be physically repositioned. With SSDs, the random/sequential access distinction is much less relevant. Data are put wherever the controller wants it, so the idea that the operating system sees one piece of information next to another is mostly just an illusion.
4 KB Random Reads
All four M500s turn in similar performance up to a queue depth of four, but begin to diverge with eight commands outstanding. At a queue depth of 16, the differences are even more pronounced, resulting in a nearly 20,000 IOPS delta between the largest and smallest models. Double the queue depth from there, and the 240 GB version pulls up alongside the 960 and 480 GB configurations.
Even the 120 GB M500 comes off smelling like a rose compared to Intel's SSD 335. Overall, though, the m4's successor just can't catch the more elite SSDs at higher queue depths. The situation is far more favorable at lower queue depths, which is good news for Crucial, since that's where a majority of desktop workloads are reflected.
We can isolate maximum 4 KB read performance for a little extra context. There is some separation, but it's not very significant. As with the sequential reads, we're not particularly surprised to see such a small delta between most of the models on this chart. It doesn't take much flash to achieve spectacular read performance. The big differentiation happens in our write tests.
