
Intel Optane DC Persistent Memory, a year later

Last summer, we announced Optane DC Persistent Memory on our blog - Optane memory based on 3D XPoint modules in DIMM format. As it was then announced, deliveries of Optane strips began in the second quarter of 2019, by this time enough information had accumulated about them that was so lacking then, during the announcement. So, under the cut - technical specifications and usage models of Optane DC Persistent Memory , as well as all sorts of infographics.
So, as already mentioned, Optane DC Persistent Memory (Optane DC PM) modules are installed in standard DDR4 DIMM slots, however, their use requires support by a memory controller, so this kind of memory can only be used with Intel Xeon Scalable Gold or Platinum second generation processors . In total, one Optane DC PM module can be installed per memory channel, that is, up to 6 modules per socket, that is, a total of 3 TB or 24 TB per 8-socket server.

The Optane DC PM comes in 3 sizes: 128, 256 and 512 GB - much larger than the DDR DIMMs currently available. There are two main ways to use it and interact with traditional memory.
- Memory mode - does not require any application modifications. In this mode, Optane DC PM is used as the main addressable RAM, and the existing amount of traditional DRAM is used as the cache for Optane. The memory mode allows you to provide applications with a significant amount of RAM at a significantly lower price, which can be important when hosting virtual machines, large databases, and so on. It should be borne in mind that in this mode Optane DC Persistent Memory is volatile, since the data in it is encrypted with a key that is lost during a reboot.
- Direct access mode - applications and software have the ability to directly access Optane DC PM, which simplifies the call chain. Also in this mode, you can use the existing API storage tools, which allows you to work with memory as an SSD and, in particular, boot from it. The system sees Optane DC PM and DRAM as two independent memory pools. Your advantage is a large, non-volatile, fast and reliable storage for demanding data exchange applications and system needs.
An intermediate option is also possible: some of the Optane DC PM strips are used in memory mode, and some in direct access mode. The following slide shows the benefits of using Intel Optane DC Persistent Memory for hosting virtual machines.

Now we give the performance characteristics of the memory modules.
Volume | 128 gib | 256 gib | 512 gib |
Model | NMA1XXD128GPS | NMA1XXD256GPS | NMA1XXD512GPS |
Warranty | 5 years | ||
AFR | ≤ 0.44 | ||
Endure 100% Recording 15W 256B | 292 PBW | 363 PBW | 300 PBW |
Endurance 100% Record 15W 64B | 91 PBW | 91 PBW | 75 PBW |
Speed 100% reading 15W 256B | 6.8 GB / s | 6.8 GB / s | 5.3 GB / s |
100% write speed 15W 256B | 1.85 GB / s | 2.3 GB / s | 1.89 GB / s |
Speed 100% reading 15W 64B | 1.7 GB / s | 1.75 GB / s | 1.4 GB / s |
100% write speed 15W 64B | 0.45 GB / s | 0.58 GB / s | 0.47 GB / s |
DDR Frequency | 2666, 2400, 2133, 1866 MT / s | ||
Max. TDP | 15W | 18W |