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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.

The RD400 instantly stakes its claim as part of the new breed, posting the kind of four-digit speeds we haven't seen since we reviewed Samsung's 950 Pro. The sequential read rates at QD4 are a hair's breadth away from 2000 MB/s, a barrier no drive we've tested yet has broken. The RD400's sequential write speeds are no less impressive, beating out Samsung's V-NAND-equipped 950 Pro by at least a 30% margin at both queue depths.

The RD400's random response times don't blow us away in the same way its sequential speeds do, but they're still quite respectable. Intel's 750 Series drive fares better in our tests, but the version in our result dataset is the 1.2TB drive, which has a natural advantage over the RD400 512GB thanks to its extra capacity.