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IOMeter — Sequential and random performance

IOMeter fuels much of our latest storage test suite, including our sequential and random I/O tests. These tests are run across the full capacity of the drive at two queue depths. The QD1 tests simulate a single thread, while the QD4 results emulate a more demanding desktop workload. For perspective, 87% of the requests in our old DriveBench 2.0 trace of real-world desktop activity have a queue depth of four or less. Clicking the buttons below the graphs switches between results charted at the different queue depths. Our sequential tests use a relatively large 128-KB block size.

Starting off, the P1's sequential read speeds are peppy. The PCIe P1 offers better read performance than SATA drives, but it can't keep up with the NVMe TLC pack. As for sequential writes... oy vey, to borrow from the Yiddish. Dynamic Write Acceleration has succumbed to the challenges of our IOMeter test methods. Our full-drive write often foils drives' caching schemes and exposes the pokey raw speeds concealed beneath them. That's precisely what happened in our IOMeter tests of the 860 QVO.

In this case, however, the performance falloff is even worse than that. The SM2263 has no direct-to-flash capability, meaning it can't intelligently decide to bypass the saturated pseudo-SLC cache and commit directly to QLC. So the paltry speeds we're seeing represent a cascading effect of queued writes waiting for previous writes to finish and corresponding cache to be cleared before they can be serviced.

Our real-world tests later on don't fill the drive's entire span, so there's still hope that the P1 might perform better under less strenuous conditions. But it won't escape the effect these figures have on its overall ranking.

Random read response times are slower than most of the other PCIe drives, but way faster than the 860 QVO's. Random write response times are solid, falling towards the middle of the pack.

Sequential writes were a disaster for this drive, but elsewhere, the P1 seems to perform as we expected: about as well as SATA TLC drives, but worse than PCIe TLC drives. Let's throw some more tests at it.