The HP EX920 M.2 SSD Review: Finding the Mainstream Sweet Spot

Mixed Random Performance

Our test of mixed random reads and writes covers mixes varying from pure reads to pure writes at 10% increments. Each mix is tested for up to 1 minute or 32GB of data transferred. The test is conducted with a queue depth of 4, and is limited to a 64GB span of the drive. In between each mix, the drive is given idle time of up to one minute so that the overall duty cycle is 50%.

None of the flash-based SSDs can come close to the performance of Intel's Optane SSDs on the mixed random I/O test. But setting that aside and looking only at the drives that are priced close enough to be in direct competition, the HP EX920's performance is great: it narrowly beats the WD Black and is surpassed only by Samsung's top drives. The 1TB EX920 is substantially faster than the smaller Intel 760p and more than twice as fast as the Crucial MX500 SATA SSD.

Power Efficiency in MB/s/W	Average Power in W

The power efficiency of the EX920 during the mixed random I/O test is nothing special. As with many other tests, the HP draws more power than most drives, leading to poor efficiency when it can't also deliver top performance. The WD Black offers about the same performance with a 2W power draw instead of the 3W the HP requires, which allows the WD Black to beat even the super-fast Optane SSD for efficiency.

HP EX920 1TBIntel SSD 760p 512GBSamsung 960 EVO 1TBSamsung 960 PRO 2TBSamsung 970 EVO 1TBOCZ RD400 1TBWD Black 1TB (3D NAND)Toshiba XG5 1TBPlextor M9PeGN 1TBCrucial MX500 1TBKingston A1000 960GBIntel Optane SSD 900P 280GBPatriot Hellfire 480GBIntel SSD 600p 512GB

The HP EX920's performance accelerates throughout the mixed random I/O test as the proportion of writes increases. What holds it back is the lack of a large performance spike in the final phase of the test when the workload is 100% writes. The EX920 ends the test about 200MB/s slower than it would if its performance scaled as well as the 970 EVO.

Mixed Sequential Performance

Our test of mixed sequential reads and writes differs from the mixed random I/O test by performing 128kB sequential accesses rather than 4kB accesses at random locations, and the sequential test is conducted at queue depth 1. The range of mixes tested is the same, and the timing and limits on data transfers are also the same as above.

The HP EX920 doesn't offer the fastest performance on the mixed sequential I/O test, but it does maintain an average that's well above 1GB/s and close enough to the top drives that the difference would be barely noticeable without our benchmarking tools. The EX920 is substantially faster than drives like the Toshiba XG5 and Plextor M9Pe that also use 64L 3D TLC, and it's almost four times faster than the Crucial MX500 SATA SSD.

Power Efficiency in MB/s/W	Average Power in W

As usual, the HP EX920 draws quite a bit of power-almost as much as the Samsung 970 EVO. Since the EX920 doesn't offer quite the same level of performance, its efficiency score suffers but remains ahead of the older generation of high-end NVMe SSDs.

HP EX920 1TBIntel SSD 760p 512GBSamsung 960 EVO 1TBSamsung 960 PRO 2TBSamsung 970 EVO 1TBOCZ RD400 1TBWD Black 1TB (3D NAND)Toshiba XG5 1TBPlextor M9PeGN 1TBCrucial MX500 1TBKingston A1000 960GBIntel Optane SSD 900P 280GBPatriot Hellfire 480GBIntel SSD 600p 512GB

Like most high-end SSDs, the HP EX920's worst performance comes in the second half of this test, when there are more writes than reads but not quite enough writes to make the most of write combining and caching. The EX920 again shows less improvement than most drives when the workload finally transitions to pure writes, but the solid performance during the read-heavy half of the test and a worst case performance that barely dips below 1GB/s helps the EX920 maintain a great overall average.