Sustained and scaling I/O rates
Our sustained IOMeter test hammers drives with 4KB random writes for 30 minutes straight. It uses a queue depth of 32, a setting that should result in higher speeds that saturate each drive's overprovisioned area more quickly. This lengthy—and heavy—workload isn't indicative of typical PC use, but it provides a sense of how the drives react when they're pushed to the brink.
We're reporting IOps rather than response times for these tests. Click the buttons below the graph to switch between SSDs.
The MP500's doesn't present the huge early burst speed that's typical of many SSDs. It does start off writing noticeably faster than its eventual steady state, but the gap is narrower than we usually see. The next graphs will plot its sustained performance more plainly against the competition.
It is a relatively low peak, but not all that much lower than the RD400's. The Hellfire's was much higher, but perhaps we can chalk that up to how PS5007-E7 handles at different capacities. In better news, the MP500's steady-state write rate is up there with the best and brightest, eclipsing both the Hellfire and the RD400.
Our final IOMeter test examines performance scaling across a broad range of queue depths. We ramp all the way up to a queue depth of 128. Don't expect AHCI-based drives to scale past 32, though—that's the maximum depth of their native command queues.
For this test, we use a database access pattern comprising 66% reads and 33% writes, all of which are random. The test runs after 30 minutes of continuous random writes that put the drives in a simulated used state. Click the buttons below the graph to switch between the different drives. And note that the P3700 plot uses a much larger scale.
Again, we see echoes of the Hellfire. The MP500 scales smoothly all the way to QD128, with no stalling or stuttering along the way. Hats off to Phison—the E7 is two for two in this test. And it has a leg up on the competition, as the next graphs will demonstrate.
Despite its lower capacity, the MP500 240GB every so slightly edges out the Hellfire 480GB. OCZ's RD400 and Samsung's 960 EVO 250GB both fizzle out around QD16. Phison's figured out how to squeeze more scaling oomph out of Toshiba's 15-nm MLC than Toshiba itself.
The MP500 suffered from a low peak in our sustained write benchmark, but performed flawlessly in our scaling testing. It's time to put aside IOMeter and see how the drive does in the real world.