The Intel Optane SSD 900P 280GB Review
by Billy Tallis on October 27, 2017 9:30 AM ESTDrive Features
Intel's strategy for developing the Optane SSD 900P is the same they used for the SSD 750 in 2015. Both products are consumer-oriented derivatives of the flagship enterprise SSD of their time. As with the SSD 750, this has resulted in the Optane SSD 900P being a physically large and power-hungry drive that can't come close to fitting in the M.2 form factor used by most other consumer PCIe SSDs. The controller alone on the Optane SSD 900P is too large to fit on a 22mm-wide M.2 module, and its idle power draw of 5W is more than most M.2 PCIe SSDs draw under load.
The Optane SSD 900P shares the same platform as the enterprise Optane SSD DC P4800X. It uses the same Intel controller with a PCIe 3.0 x4 link to the host system and a seven channel interface to the 3D XPoint memory. The P4800X is available as a 375GB drive that uses four dies per channel for a raw capacity of about 448GB. The 900P uses three or five dies per channel and similar overprovisioning ratios to offer usable capacities of 280GB and 480GB from raw capacities of about 336GB and 560GB. Because 3D XPoint memory supports direct read and in-place write operations with bit granularity instead of being constrained by the page and block structure of NAND flash memory, the Optane SSD 900P isn't using the extra capacity as spare area for any garbage collection process and is likely instead devoting most of it to error correction overhead and metadata.
The odd capacities and channel counts of the Optane SSD 900P aren't a requirement for using 3D XPoint memory so much as they are a consequence of Intel's performance and power targets for the drive. However, the use of 3D XPoint memory does lead to a few striking hardware design differences from flash-based SSDs. The Optane SSD 900P does not have any DRAM cache. On a NAND flash-based SSD, this would be a major red flag indicating reduced performance, even when mitigated by the NVMe Host Memory Buffer feature. Flash-based SSDs need quick access to the mapping tables that track which logical blocks are stored in which physical pages. 3D XPoint memory, on the other hand, is much simpler to manage, with no need for garbage collection and little or no need for wear leveling, and the storage medium itself is far faster. This makes the large DRAM buffer unnecessary.
The lack of buffers seems to also extend to the individual 3D XPoint chips themselves. NAND flash dies include page-sized RAM buffers as intermediate storage between the controller and the flash memory array. This allows the controller to transfer the payload data for a write command to the NAND die and then move on to issuing other commands to other dies on the same memory channel (or other planes on the same die) while the relatively long NAND program operation is happening. This multiplexing of operations within a single memory channel is a large part of why flash SSDs tend to be faster at higher capacities even within the same product line with the same SSD controller. The Optane SSD 900P accesses its 3D XPoint memory more directly and read and write operations are completed synchronously without an intermediate buffering stage. This means that the 280GB and 480GB models have essentially the same performance, and this same level of performance could in theory extend down to a one die per channel configuration that would offer 112GB raw capacity and 96GB usable capacity (and could be profitably sold for under $180).
While the lack of RAM buffers on the Optane SSD doesn't bring any major performance problems, it does have one minor downside. Flash-based SSDs are able to aggressively take advantage of their buffers to accept write operations almost as fast as the PCIe link allows for, so the Optane SSD 900P doesn't have much room to improve peak write speeds beyond what the 3D XPoint memory itself can sustain. However, the Optane SSD can continue providing those write speeds long after a flash-based SSD would have stalled to let the flash catch up to the controller.
The last major implication of the DRAMless design of the Optane SSD 900P is that large banks of capacitors are unnecessary to provide power loss protection. The Intel SSD 750 was one of the few consumer SSDs to offer enterprise-grade power loss protection, but those capacitors added to an already high BOM and were probably only kept to save the effort of more significant firmware changes relative to the enterprise SSDs it was based on. With the Optane SSD 900P, Intel gets to retain power loss protection on the consumer version more or less for free. This allows the Optane SSD 900P to avoid the consequences of Microsoft's stupid NVMe driver write cache policy defaults, which severely curtail the write performance of consumer NVMe drives that have volatile write caches. (Our client SSD test protocol uses the more reasonable but non-default write buffer policy for all Windows-based tests, so this advantage doesn't show up in out performance charts.)
When an SSD vendor makes consumer and enterprise drives based on the same controller platform, there are usually major firmware differences to optimize for different performance requirements. Consumer SSDs tend to use SLC write caching to offer better burst write performance while enterprise SSDs tend to avoid it to offer more consistent performance. There are few opportunities with the Optane SSD to tweak performance between the consumer and enterprise versions, but there are several features from the P4800X that have been omitted from the 900P. The only one that has any performance impact is the ability to reformat the P4800X to use a 4kB logical block size instead of 512 bytes; the 900P only supports 512B sectors and doesn't support end-to-end data protection. The 900P also omits the SMBus interface for out of band management and doesn't include the diagnostic LEDs.
The most significant functional difference between the P4800X and the 900P is the endurance rating, which has been reduced from 30 drive writes per day to 10 DWPD. That's still a very high figure for a consumer SSD, but Intel's policy of putting the drive into read-only mode when the rated endurance is reached can be a nuisance, and it'll be encountered sooner on the 900P. The difference in write endurance is proportional to the price difference between the 900P and the P4800X, so the de-rating isn't too unfair. Overall, the Optane SSD 900P is still the closest a consumer SSD gets to offering enterprise SSD performance and features, and the 900P will probably cannibalize some P4800X sales.
Note that our usual set of power measurements is unavailable due to an equipment failure. The Optane SSD 900P will be re-tested once we have a new power meter, and the results will be posted to the SSD Bench database. In the meantime, rest assured that the Optane SSD 900P won't win any awards for efficiency.
| AnandTech 2017 SSD Testbed | |
| CPU | Intel Xeon E3 1240 v5 |
| Motherboard | ASRock Fatal1ty E3V5 Performance Gaming/OC |
| Chipset | Intel C232 |
| Memory | 4x 8GB G.SKILL Ripjaws DDR4-2400 CL15 |
| Graphics | AMD Radeon HD 5450, 1920x1200@60Hz |
| Software | Windows 10 x64, version 1703 |
| Linux kernel version 4.12, fio version 2.21 | |
- Thanks to Intel for the Xeon E3 1240 v5 CPU
- Thanks to ASRock for the E3V5 Performance Gaming/OC
- Thanks to G.SKILL for the Ripjaws DDR4-2400 RAM
- Thanks to Corsair for the RM750 power supply, Carbide 200R case, and Hydro H60 CPU cooler
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Kevin G - Monday, October 30, 2017 - link
The software side does lag behind hardware by a substantial amount of time. However, the ground work is already being done. The first initial wave of support will be mundane as a 'RAM disk' but with firmware/hypervisor/OS support so that only Optane DIMMs are utilized for this functionality. Software overhead would still exist for the file system but legacy support would be maintained. I think patches already exist for this level of functionality in Linux, though I'm unsure if they're been rolled into the mainstream kernel.Kevin G - Monday, October 30, 2017 - link
Intel still has this potential on their road maps for 2018 with the Cascade Lake Xeons. Supporting Optane as memory requires some changes in the memory controllers and Intel is only targeting their Xeon lineup with such support. This was initially to arrive with Sky Lake-EP but was cut at the last minute due to apparently some bugs found in testing. This is what there are a few Sky Lake-EP motherboards out there with an extra memory slot that can't be used: it was only for the unreleased Optane DIMMs.The other thing is that Optane DIMMs were NEVER hyped to be faster than commodity DRAM. Intel never set that expectation and from all accounts, Optane is genuinely slower. However, byte addressability is there as is a strong increase in endurance for it to function in such a role, if slower. Any sort of performance gains will stems form various ideas that you mention, like the removal of a traditional storage stack etc.
The other side of storage is capacity which Intel has really yet to demonstrate. Their talk of Optane DIMMs were to hit 1 TB per DIMM eventually but the sizes here point toward capacities in DIMM format roughly the same as traditional DIMMs (128 GB right now in servers with 256 GB on the horizon). I know of a few big data guys that dream of a system that could easily support 96 TB (1 TB DIMM per slot, 12 DIMM slots per socket, 8 sockets total) that would permit their entire cluster to be run on a single node and in-memory. At this point having the Optane DIMMs being slower than DRAM wouldn't matter as it would eliminate traditional bulk storage and networking overhead which are slower still. The potential is huge at the highend if Intel can get the technology out in the right form factor and at the capacities they need.
Only reason Intel is launching like this now is that they need to get the technology out there and ramp up production. If it weren't for the Sky Lake bug, they would have launched the DIMM format by now.
4shrovetide - Sunday, October 29, 2017 - link
If someone picks up one of these and doesn't play games or just doesn't want the Star Citizen code, would you mind sending it to me? 4shrovetide@gmail.com Thank you in advance to anyone who helps out!AnnonymousCoward - Sunday, October 29, 2017 - link
What a copycat name, 900P! Like 950 Pro.Kevin G - Sunday, October 29, 2017 - link
I'm disappointed over all.The latency advantage is genuinely there as is random performance (which latency is factor in itself) but sequential performance falls short of the hype. What is disappointing as well is that only the 280 GB drive is going to be offered in U.2 format and capacities top out at 480 GB even of the add-in card model. The real ugly factor is power consumption which to Intel's credit wasn't hyping up prior to launch is high relative to other SSD solutions.
The biggest promise of 3D Xpoint/Optane is in DIMM form factor with byte addressability. Intel delayed that last minute with Sky Lake-EP and told people to expect that with Cannon Lake-EP. It looks like Cannon Lake-EP is being delayed due 10 nm issues into 2019 so we're getting a 2018 refresh of Sky Lake-EP called Cascade Lake with the missing Optane DIMM support back-in. The hype of Optane was that while radically slower than DRAM, you do get nonvolatile support and a massive capacity increase, everything else being equal. The performance equation does change as operating system and applications are adapted to an all in-memory centric view (i.e. the concept of long term disk storage is removed, everything is seen as 'in-memory'). It isn't that Optane magically becomes faster but simply that a chunk of software necessary to work in today's view of fast volatile memory and slow persistent memory is no longer needed. It is simply an opportunity to gain in algorithmic efficiency by not having a traditional storage stack. This effect can be seen again if Optane DIMM sizes are well beyond that of DDR4 DIMMs and used in conjunction with large socket (think 8 or more) that could replace some clustered workloads and removing the networking stack from the performance equation.
The really big disappointment is this launch doesn't point toward living up to the remaining hype at all. The lack luster capacity today certainly implies that the DIMM sizes necessary to threaten DRAM may not happen. 128 GB registered ECC DDR4 LR-DIMMs are out there today and 256 GB models are on the horizon. From the looks of it, Optane could make the 256 GB capacities in DIMM form and certainly come in cheaper but that wouldn't be as large of a game changer. Sure, the software changes for a pure in-memory system could still happen but it wouldn't enable any new workload that couldn't be done via current software and memory capacities. Tried and proven will win out even if it is more expensive because it is known quantity that works.
"Bullwinkle J Moose" - Monday, October 30, 2017 - link
Any thoughts on Advanced Persistent Threats that will be lingering around when 3D Xpoint/Optane is in DIMM form factor ?Seems no-one has yet been willing to address the issue
I would never consider persistent memory for just that reason alone
And, swapping boot drives or restoring backups won't help it seems
Any comments on the issue?
Kevin G - Monday, October 30, 2017 - link
While a threat may persist in non-volatile memory, it still needs to be executed which is invoked from the host system. Cleansing an Optane DIMM maybe as simple as putting it into a system that is programmed to immediate wipe said Optane DIMM. There will always need to be a means to do some initial configuration/initialization which would be embedded at the firmwire level. In other words, the DIMMs don't have to be running an OS for them to be securely erased.Similarly, moving a DIMM from one system to another system is also possible, though the default should actually be to do nothing by default. As weird as it is, there exists the possibility of moving a running application from system to system by this method. This goes to your point about security. Thus the default for any system capable of hot swap or detecting a newly installed DIMM after power cycle, should not actually access the contents of that DIMM until given instructions to access it.
"Bullwinkle J Moose" - Monday, October 30, 2017 - link
But wiping the DIMM defeats its very purpose for existing..............PERSISTENCE!Kaspersky found out how bad malware can be when it only runs in system memory and never touches a disk, networking the infected systems added persistence to the threat
If you need to wipe the DIMM or disconnect from any networked machines, you eliminate any tiny perceived benefit this technology "could" give you over the tech we already have
I say "Tiny" benefit only as it relates to the "massive" threat it can create from being persistent
regis440 - Monday, October 30, 2017 - link
Faster then SDRAM PC133. Sign of the time :)jrs77 - Monday, October 30, 2017 - link
General purpose storage starts at a very minimum of 1TB these days. 2TB would be more appropiate with the ever growing filesizes of high resolution video and image-files.480GB is filled up with a handfull of game-installations allready these days. So these SSDs are only usable as OS/software disks and for that the price is way too high.
Call me again when SSD-prices drop to ~ $100 / TB. Then we're talking usability as general storage drives.