The HP S700 And S700 Pro SSD Review

Final Words

The HP S700 is in theory handicapped by its DRAMless controller. Random access performance in particular suffers without a DRAM cache, and garbage collection on a near-full drive is more of a chore. This doesn't necessarily translate to a significant disparity in real-world performance. The S700 falls behind on the heaviest real-world tests and performs much worse when it is full, but on more common lighter workloads and with plenty of unused capacity, it is not immediately obvious that the drive is DRAMless. On workloads where the S700's performance doesn't tank, it also offers great power efficiency. Its apparent inability to enter the slumber idle power state prevents me from recommending it for mobile use, but this issue may be fixable with a firmware update. The S700 also offers a surprisingly high sequential read speed, much better than any other SATA SSD using Micron 3D NAND, including the S700 Pro and even the MLC-based Crucial BX300.

The HP S700 Pro is in closer competition with the kinds of SATA SSDs we typically review. The S700 Pro uses the same NAND and the same controller as the ADATA SU800 we reviewed earlier this year. HP's firmware tuning clearly pays off, as the S700 Pro outperforms the SU800 across the board in both performance and power efficiency. The improvement is seldom enough to allow the S700 Pro to deliver mid-range performance like the Crucial MX300, but it's clear the S700 Pro is more refined than the SU800. The S700 Pro also handles operating in a nearly-full state much better than the SU800, and the 512GB S700 Pro's performance is barely affected by being full. We suspect the 1TB S700 Pro will also offer similarly good all-around performance with few caveats. The 256GB S700 Pro's performance will drop on a wider range of workloads but is still decent.

Building a SSD with decent performance in the 120/128GB capacity class is quite challenging with modern NAND flash chips that mean the drive will only have three or four dies to stripe accesses across. Several vendors no longer attempt this and start even their entry-level SSD product lines at 240GB or more. With NAND flash prices elevated by a shortage, there's still some demand for smaller SSDs. Crucial just re-entered this product segment with the MLC-based BX300, but we haven't yet had the chance to confirm whether the 120GB BX300 performs as well as its larger versions suggest is should. Aside from the BX300, it looks like the 128GB HP S700 Pro is probably one of the best performers in that capacity class from the current or previous generation of SSDs. However, everything in this capacity class is at a substantial disadvantage to larger drives, and this will continue to be the case unless someone starts manufacturing 128Gb 3D NAND dies.

We're not sure if Micron is selling the Crucial BX300 at a loss, but they're certainly selling it with slimmer margins than most budget SSDs. While this pricing holds, there's no reason to consider drives with Micron's TLC, and the next step up would be the Samsung 850 EVO. At the moment, the 500GB 850 EVO is even cheaper than the BX300. Meanwhile, the HP S700 isn't consistently cheaper than the S700 Pro, and the latter is substantially more expensive than the BX300 except at the smallest capacity.

While the HP S700 and S700 Pro are not currently priced competitively, they do show that there's value in continued firmware tuning. More than a year after Micron's 32-layer 3D NAND hit the market, the HP S700 sets a new record for sequential read performance from a four-channel controller, and helps show that DRAMless SSDs can't be immediately dismissed from consideration. The S700 Pro improves on the performance that can be obtained from the combination of Micron's 32L 3D TLC and the SM2258 controller, which are now both nearing the end of their product cycles. These improvements bring the SM2258 controller into closer competition with the more expensive Marvell controllers.