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.
The 860 QVO's sequential reads can't keep up with those of the TLC-equipped 860 EVO, but the race is fairly close. On the other hand, writes aren't at all in the same ballpark. It's worth noting that our sequential IOMeter test setup defeats schemes like Intelligent TurboWrite by design. The test file IOMeter runs spans the entire capacity of the drive, so there's never any idle space to take advantage of. But that was true for the 860 EVO as well, and it chugs along happily near 500 MB/s on static TurboWrite alone. We know that the performance of direct-to-QLC writes is relatively poor from Samsung's materials, so we're most likely seeing the effects of that characteristic here.
It's worth noting that IOMeter is a stress test, and this is the sort of issue that real-world workloads don't typically expose. We'll reserve final judgement on the drive's write capabilities for now, but this is a black mark that will hurt the 860 QVO in our aggregated rankings.
Life doesn't get better for the QVO in our random tests. Random read response times are slower than even our ancient X25-M. Maybe don't throw our your SATA 3 Gbps drives just yet, especially if they're packing MLC inside. The 860 QVO surges to life when it comes to random write response times. Clearly its TurboWrite tricks yield good results when they kick in properly.
Our first set of IOMeter tests leave us with doubts about the 860 QVO and QLC's place in the SSD landscape. Let's see what our sustained and scaling tests can uncover.