The Intel Optane Memory H10 Review: QLC and Optane In One SSDby Billy Tallis on April 22, 2019 11:50 AM EST
The idea behind the Optane Memory H10 is quite intriguing. QLC NAND needs a performance boost to be competitive against mainstream TLC-based SSDs, and Intel's 3D XPoint memory is still by far the fastest non-volatile storage on the market. Unfortunately, there are too many factors weighing down the H10's potential. It's two separate SSDs on one card, so the NAND side of the drive still needs some DRAM that adds to the cost. The caching is entirely software managed, so the NAND SSD controller and the Optane controller cannot coordinate with each other and Intel's caching software sometimes struggles to make good use of both portions of the drive simultaneously.
Some of these challenges are exacerbated by benchmarking conditions; our test suite was designed with SLC write caching in mind but not two layers of cache that are sometimes functioning more like a RAID-0. None of our synthetic benchmarks managed to trigger that bandwidth aggregation between the Optane and NAND portions of the H10. Intel cautions that they have only optimized their caching algorithms for real-world storage patterns, and it is easy to see how some of our tests have differences that may be very significant. (In particular, many of our tests only give the system the opportunity to use block-level caching, but Intel's software can also perform file-level caching.) But this only emphasizes that the Optane Memory H10 is not a one size fits all storage solution.
For the heaviest, most write-intensive workloads, putting a small Optane cache in front of the QLC NAND only postpones the inevitable performance drops. In some cases, trying to keep the right data in the cache causes more performance issues than it solves. However, the kind of real-world workloads that generate that much IO are unlikely to run well on a 15W notebook CPU anyways. The Optane cache doesn't magically transform a low-end SSD into a top of the line drive, and the Optane Memory H10 is probably never going to be a good choice for desktops that can easily accommodate a wider range of storage options than a thin ultrabook.
On lighter workloads that are more typical of what an ultrabook is good for, the Optane Memory H10 is generally competitive with other low-end NVMe offerings and in good conditions it can be more responsive than any NAND flash-only drive. For everyday use, the H10 is certainly preferable over a QLC-only drive, but against TLC-based drives it's a tough sell. We haven't had the chance to perform detailed power measurements of the Optane Memory H10, but there's little chance it can provide better battery life than the best TLC-based SSDs.
If Intel is serious about making QLC+Optane caching work well enough to compete against TLC-only drives, they'll have to do better than the Optane Memory H10. TLC-only SSDs will almost always have a more consistent performance profile than a tiered setup. The Optane cache on the H10 doesn't soften the rough edges enough to make it suitable for heavy workloads, and it doesn't enhance the performance on light workloads enough to give the H10 a significant advantage over the best TLC drives. When the best-case performance of even a QLC SSD is solidly in "fast enough" territory thanks to SLC caching, the focus should be on improving the worst case, not on optimizing use cases that already feel almost instantaneous.
Optane has found great success in some segments of the datacenter storage market, but in the consumer market it's still looking for the right niche. QLC NAND is also still relatively unproven, though recently it has finally started to deliver on the promise of meaningfully lower prices. The combination of QLC and Optane might still be able to produce an impressive consumer product, but it will take more work from Intel than this relatively low-effort product.