Ever since Intel announced that it had created a new type of non-volatile memory in partnership with Micron, dubbed 3D XPoint, there have been questions about how the new memory would perform and what kind of systems might ship it in the future.
The ostensible draw of alternative memory technologies like 3D XPoint (Intel markets its drives under the Optane brand) is that it can offer non-volatile storage performance at speeds more comparable to DRAM, but with better power consumption. Discussions on cost are less certain — right now, Intel and Micron are focused on introducing the technology and it’ll be fairly expensive for the near-term future. Long-term price is an unknown — the sheer economy of scale around NAND flash makes it difficult for any new storage technology to challenge in terms of cost-per-GB. Now, however, we have some idea how Optane will perform, at least in Intel’s initial data center SSD.
Intel’s P4800X series is a 375GB drive with sequential read/write speeds of 2400MB/s and 2000MB/s respectively. Random 4KB IOPS are rated at 550K/s for reads and 500K/s for writes. Overclockers3D points out that this compares extremely favorably with Samsung’s 960 Pro SSD, which offers up to 330K IOPS for random 4KB reads and writes. Still, it’s worth bearing in mind that IOPS are substantially meaningless without a great deal of information about how the tests were conducted and how the workloads were designed. On their own, they don’t tell us much.
One thing we do know, however, is that Optane can deliver excellent performance even with a queue depth of 1. Queue depth refers the number of commands that can be queued within a storage controller at the same time. A queue depth of 32 is commonly used when testing desktop applications and software, and as you can see, a queue depth of 1 produces poor performance on an SSD.
The graph above is from my own system, using a spare SSD I’ve got installed. At a queue depth of 32, the SSD is 7.82x faster than with a queue depth of 1 in 4K random reads. The gap between write speed is less dramatic, but QD=32 is still 2.23x faster than QD=1. Typically, storage workloads stack up large queue depths and high-end hardware controllers can handle far more than the 32 queues specified in SATA — but if Optane can deliver excellent performance at low queue depths as well as high, it could prove a potent competitor in any workload dominated by such metrics.
These are the first Optane drives, and they’re intended for data centers, not consumers. Intel does have plans to make Kaby Lake accelerators available to customers with a Z270 chipset, but pricing and availability have not been announced.
Now read: How do SSDs work?