The HP 900 is company's USB 3.2 Gen 2 20 Gbps flagship portable solid-state-drive. It uses the Silicon Motion SM2320G controller, which combines the USB interface and SSD controller into a single IC. This helps reduce cost and complexity, as just one instead of two chips is required. Obviously, this also means that drives can be more compact, because components are more tightly integrated. In terms of NAND flash, we found Micron's 176-layer 3D TLC NAND. Unlike many other vendors, which build external SSDs by including a full-sized M.2 NVMe inside the case, HP was smart, choosing to go with a proper, highly compact design. As a result, you get a compact portable high-performance SSD—most competitor products are considerably bigger, some are smaller though.

Performance numbers of the HP 900 are quite decent, but it ends up a little bit slower than some competing models. Sequential reads and writes reach well over 1 GB/s. As expected, there is no DRAM cache for the mapping tables of the SSD, to optimize random writes. However, that isn't a dealbreaker, as it is an ultra-rare workload for a portable SSD.

The physical construction of the HP P900 is great, thanks to its all metal shell. The matte paint job looks fantastic and is fairly resistant to fingerprints. I do miss an activity indicator LED, which would be useful to get a feel for when an operation has completed. Temperatures were no problem on the P900—it gets just warm, not hot.

Sustained write speeds of the HP SSD aren't that impressive. With just 180 MB/s to fill the whole disk, it's slower than many of its competitors, but considerably faster than the Crucial X8, for example. If you plan on copying hundreds of gigabytes per session without pause, then look elsewhere. If your working sets are smaller, up to 60 GB writes, or so, or you have pauses in transfers that give the drive room to breathe, the P900 will run much faster, reaching around 1000-1400 MB/s—the pseudo-SLC cache size is 80 GB, which is "okay" for a 1 TB drive.

While it's not available in the West, the HP P900 is currently listed in China for $68. For a 1 TB USB 3.2 2x2 enclosure that's an excellent price. At sub-$70, the P900 is basically the most affordable 20 Gbps drive, reaching price points offered by 10 Gbps drives. There's a bunch of strong competitors like the Kingston XS2000 ($95), the ADATA SE880 ($80), the Corsair EX100U ($80) and of course the Sabrent Rocket Nano V2 ($90). If you plan on using the HP P900 in your system you have to make sure that there's support for the USB 3.2 2x2 20 Gbps interface technology, which might be a problem for older PCs. For specific use-cases, i.e. not sequential reads or writes, a 10 Gbps drive should be "good enough" and a bit more economical. I only wish HP offered a 4 TB version, which is a capacity that's becoming more and more interesting due to the recent drop in NAND flash prices.