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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 128KB block size.



Both versions of the SSD370 are off to a robust start in these tests. The 256GB drive's sequential reads are faster than much of its competition and even some higher-capacity drives. Among SATA drives of a similar size, only the 850 EVO 250GB and Vector 180 240GB post appreciably faster speeds. The 1TB drive's sequential reads are in line with both the 850 EVO 1TB and 850 Pro 512GB, which are honorable company indeed.

The drives' sequential writes are a bit less impressive, but respectable nonetheless. The SSD370 256GB falls short of a number of its contemporaries, like the Arc 100 240GB and Vector 180 240GB. The 256GB drive remains neck-and-neck with the 850 EVO 250GB, though. The SSD370 1TB's sequential writes fall behind the Samsung heavyweights, but it keeps pace with the only other non-Samsung high-capacity SATA drive in this dataset, OCZ's Vector 180 960GB.

Next, we'll turn our attention to performance with 4KB random I/O. The tests below are based on the median of three consecutive three-minute runs. SSDs typically deliver consistent sequential and random read performance over that period, but random write speeds worsen as the drive's overprovisioned area is consumed by incoming writes. We've reported average response times rather than raw throughput, which we think makes sense in the context of system responsiveness.



The SSD370 256GB's random read response times aren't as competitive as its sequential numbers, but they're still quite good. While it loses to the 850 EVO 250GB at both queue depths, it more or less keeps up with the OCZ and Crucial pack. On the other hand, the 1TB puts on a very strong showing, beating all other SATA drives at QD1 and losing only to a couple of Samsungs and the Intel 730 Series at QD4.

The 256GB drive finally gives us some bad news when it comes to random write response times. While it still beats the ancient Intel X25-M, the 256GB drive gets beaten badly by every other drive in the dataset. At both queue depths, it's more than twice as slow as the next-slowest drive. On the other hand, the SSD370 1TB is still on a roll, staying in the upper echelon of results.