Lenovo's announcement today of a new generation of ThinkPads based on Intel's Kaby Lake platform includes brief but tantalizing mention of Optane, Intel's brand for devices using the 3D XPoint non-volatile memory technology they co-developed with Micron. Lenovo's new ThinkPads and competing high-end Kaby Lake systems will likely be the first appearance of 3D XPoint memory in the consumer PC market.

Several of Lenovo's newly announced ThinkPads will offer 16GB Optane SSDs in M.2 2242 form factor paired with hard drives as an alternative to a using a single NVMe SSD with NAND flash memory (usually TLC NAND, with a portion used as SLC cache). The new Intel Optane devices mentioned by Lenovo are most likely the codenamed Stony Beach NVMe PCIe 3 x2 drives that were featured in roadmap leaked back in July. More recent leaks have indicated that these will be branded as the Intel Optane Memory 8000p series, with a 32GB capacity in addition to the 16GB Lenovo will be using. Since Intel's 3D XPoint memory is being manufactured as a two-layer 128Gb (16GB) die, these Optane products will require just one or two dies and will have no trouble fitting on to a short M.2 2242 card alongside a controller chip.

The new generation of ThinkPads will be hitting the market in January and February 2017, but Lenovo and Intel haven't indicated when the configurations with Optane will be available. Other sources in the industry are telling us that Optane is still suffering from delays, so while we hope to see a working demo at CES, the Optane-equipped notebooks may not actually launch until much later in the year. We also expect the bulk of the initial supply of 3D XPoint memory to go to the enterprise market, just like virtually all of Intel and Micron's 3D MLC NAND output has been used for enterprise SSDs so far.

Support for Intel Optane branded devices based on 3D XPoint memory technology has long been bandied about as a new feature of the Kaby Lake generation of CPUs and chipsets, but Intel has not officially clarified what that means. The plan of record has always been for the first Optane products to be NVMe SSDs, but NVMe is already thoroughly supported by current platforms and software. Because Optane SSDs will have a significantly higher price per GB than NAND flash based SSDs, the natural role for Optane SSDs is to act as a small cache device for larger and slower storage devices. The "Optane support" that Kaby Lake brings is almost certainly just the addition of the ability to use NVMe SSDs (including Optane SSDs) as cache devices.

At a high level, using Optane SSDs as a cache for hard drives is no different from the SSD caching Intel first introduced in 2011 with the Z68 chipset for Sandy Bridge processors and the Intel Rapid Storage Technology (RST) driver version 10.5. Branded by Intel as Smart Response Technology (SRT), their SSD caching implementation built on the existing RAID capabilities of RST to use a SSD as a block-level cache of a hard drive, operating as a write-back or write-through cache depending on the user's preference. For SATA devices, no hardware features were required but booting from RST RAID or cache volumes requires support in the motherboard firmware, and Intel's drivers have used RAID and SRT SSD caching to provide product segmentation between different chipsets.

With the release of Skylake processors and the 100-series chipsets, Intel brought support for NVMe RAID to RST version 15. This was not as straightforward to implement as RAID and SRT for SATA drives, owing to the fact that the SATA drives in a RST RAID or SRT volume are all conveniently connected through Intel's own SATA controller and managed by the same driver. NVMe SSDs by contrast each connect to the system through general-purpose PCIe lanes and can use either the operating system's NVMe driver or a driver provided by the SSD manufacturer. In order to bring NVMe devices under the purview of Intel's RST driver, 100-series chipsets have an unusual trick: when the SATA controller is put in RAID mode instead of plain AHCI mode, NVMe devices that are connected to the PCH have their PCI registers re-mapped to appear within the AHCI controller's register space and the NVMe devices are no longer detectable as PCIe devices in their own right. This makes the NVMe SSDs inaccessible to any driver other than Intel's RST. Intel has provided very little public documentation of this feature and its operation is usually very poorly described by the UEFI configuration interfaces on supporting machines. This has caused quite a few tech support headaches for machines that enable this feature by default as it is seldom obvious how to put the machine back into a mode where standard NVMe drivers can be used. Worse, some machines such as the Lenovo Yoga 900 and IdeaPad 710 shipped with the chipset locked in RAID mode despite only having a single SSD. After public outcry from would-be Linux users, Lenovo released firmware updates that added the option of using the standard AHCI mode that leaves NVMe devices alone.

(excerpt from Intel 100-series chipset datasheet)

In spite of the limitations and rough edges, Intel's solution does ensure reliable operation in RAID mode, free of interference from third-party drivers. It's certainly less work than the alternative of writing a more general-purpose software RAID and caching system for Windows that can handle a variety of underlying drivers. It also lays the groundwork for adding support for NVMe cache devices to Intel's SRT caching system. Intel's SRT already has caching algorithms tuned for 16GB to 64GB caches in front of hard drives, so now that they have a solution for mediating access to NVMe SSDs it is simple to enable using both features simultaneously. The changes do need to be added to both the RST driver and to the motherboard firmware if booting from a cached volume is to be supported. Backporting and deploying the firmware changes to Skylake motherboards should be possible but is unlikely to happen.

In the years since Intel introduced SRT caching, another form of tiered storage has taken over: TLC NAND SSDs with SLC caching. NAND flash suffers from write times that are much longer than read times, and storing multiple bits per cell requires multiple passes of writes. To alleviate this, most TLC NAND-based SSDs for client PC usage treat a portion of their flash as SLC, storing just one bit per cell instead of three. This SLC is used as a cache to absorb bursts of writes, which are consolidated into TLC NAND when the drive is idle (or when the SLC cache fills up). Even TLC NAND has reasonably high read performance, so there is little need to use SLC to cache read operations. By contrast, Intel's Smart Response Technology has to cache access to hard drives, where both read and write latencies are painfully high. This means SRT has to balance keeping frequently-read data in the cache against making room for a burst of writes. Having a lot of static data hanging around on the cache device will cause significant write amplification to result from any wear leveling, but SRT already reduces the write load by having sequential writes bypass the cache. Taking into account that 3D XPoint memory can handle millions of write operations per cell, even a small 16GB cache device should have no trouble with endurance.

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  • Kakti - Wednesday, December 28, 2016 - link

    So this is what scares me about Optane aka 3d Xpoint...they seem on par or weaker than current NAND drives due to PCI-E lanes. The drives in this article say they are PC-E 3.0 x2 drives...that's a max of ~2gig/sec, already outclassed by Samsung's newest drives (and others?). Previously they showed I believe a 3.0 x4 drive that had similar numbers, somewhat below the top end NAND drives.

    Has anything been published that 3d-Xpoint aka Optane can use a ton of lanes or something? Five years ago the numbers these drives put out would have looked great, I don't think anyone expected Samsung to basically saturate the x4 line so fast.

    Unless Optane can basically run a ton of lines in parallel I think they might be beat for what the presumed asking price is. I hope Micron and Intel can pull something out of this tech!

    *disclosure:I own Micron stock and have lost my ass over the years (but improving this year!). Everything above is my opinion only.
  • patrickjp93 - Wednesday, December 28, 2016 - link

    Are you joking? Intel's Optane drives kick the snot out of existing SSDs. Look at the QD1/2/4 numbers for the 960Pro and Intel's Optane options. Intel is the clear winner by a mile and a half. No one gets close to QD32, no one. Intel's solution will feel faster even if the peak numbers don't look so hot on 1 and 2-die solutions.
  • Kakti - Wednesday, December 28, 2016 - link

    Yeah it's supposed to have much better access/seek times (in the 120-140k IOPs range?) but whether that translates to any meaningful increase for a regular user remains to be seen. It seems like IOPS really matter on big databases and not necessarily a regular PC or most workstations.

    I dunno, I just feel this is too little to late with the small size of the new "cache/RAM drive" compared to just rolling a straight top end m.2 drive and 32gb+ of RAM.

    Anyone can make a 50gb+ ramdisk already on their workstation for a couple hundred bucks if they really need it.

    So you get 32gb of RAM and either a PCI-E x4 NVME drive or an m.2 x4 NVME drive with 500gb+...where does that leave this octane drive?

    High end users have too much ram/fast SSD to cover it. On the low end (4gb-8gb ram) it would probably shine the most but I don't know if they'll be offered in this class of products It seems like servers and databases these will do very well, so that may be the main market. I'm very curious to see some very detailed *cough* reviews once these hit the street.
  • beginner99 - Wednesday, December 28, 2016 - link

    3D XPoint is more like RAM so yes it's random performance (access times) will beat any SSD easily. And let's not forget that it was exactly this (latency) that made the biggest difference from SSD to HDD and not the sequential read/write speeds. So I can easily see that a 16 GB optane cache can make a system even with SSD much more responsive.

    And lets not forget that compared to a RAM-disk it is non-volatile. So all the cached OS files and applications are there so you will probably get a CPU limited boot and application load times! It sounds pretty cool on paper.

    Realistically even for an enthusiasts it will almost certainly not be worth it if you don't run high access databases or do some other niche level stuff.

    I'm somewhat undecided about price. The solution must obviously be cheaper than just going with an SSD. On the other hand I fear it will always be cheaper to get a faster SSD instead of adding a cache drive. Eg. if the 32 gb cache drive cost about the same as the difference between a average SSD and a 960 pro, I would choose the later,
  • iwod - Wednesday, December 28, 2016 - link

    But meaningful performance difference? SSD, at latency and certain I/O is 1000x faster then HDD. The same cant be said about Xpoint and SSD. And we surely reach a point where performance isn't in the I/O.

    i.E Starting your App from RamDisk isn't that much faster then SSD.

    What i really want to see though, is QLC, 3D stacked NAND as Storage and Xpoint as main drive. Even a 64GB main drive is good enough for me.
  • ddriver - Wednesday, December 28, 2016 - link

    Until I see optane in action I call BS. So far it looks like it will mostly have much better caching and much larger cache buffers, which will be enough to improve the IOPS regardless of the actual bulk storage medium..

    They claim "bit addressable" for optane, but that's BS too, even RAM is NOT bit addressable, not even CPU registers. RAM is BYTE addressable. Bit addressable for real would be a fruitless endeavor because the amount of extra traces will not be worth the returns, as nobody bothers with bit access.

    My bet is the medium will not even be byte addressable, they will just add that in software via bitwise ops. Much like the IOPS boost will likely be due to caching and only for cached data. All this is perfectly possible to do with NAND flash as well, as usually the industry is holding back on very logical and straightforward improvements in order to milk the most out of everything.

    So far optane has been rather hypetane... and how we get news of it making it into actual products. Oh wow, 16 gigs of optane, that's almost enough to install windoze. Paradigm shifting!
  • mdriftmeyer - Wednesday, December 28, 2016 - link

    Stop it! You're making too much sense. What you describe is a dagger into this 3D crap from Intel. Put in that 1TB or 2TB PCI-E based NVME drive and save money in the process while your system flies.
  • Billy Tallis - Wednesday, December 28, 2016 - link

    The PCIe x2 bit comes only from the months-old leaked roadmap, and we have no official confirmation of that. And for what it's worth, those roadmaps showed that only this first generation of cache drives would be so limited, while the next version will move to PCIe 3 x4.

    But the biggest advantage of 3D XPoint memory is low latency, which doesn't require a lot of PCIe lanes. And with only one or two dies, the bandwidth limitation might be between the controller and the memory, rather between the controller and the host. Larger drives suitable for primary storage rather than just caching will have the same parallelism advantages that flash SSDs enjoy, and should be much better able to deliver high throughput.

    In the meantime, these cache devices will probably offer sufficient throughput given their small capacity and the low performance of the hard drive backing devices, while not wasting power on more PCIe lanes than needed to offer the most performance benefit possible without abandoning the mechanical hard drives entirely.
  • drajitshnew - Thursday, December 29, 2016 - link

    My laptop is i7-4700mq lenovo y510p. It has a m2-2242 slot. Basically, ruling out any high performance or mainstream drives.
    My mom's laptop is i5-4200u, costed half as much, weights half as much and has an 2280 slot.
    I anticipate lenovo will DELIBERATELY cripple the sku's with optane to X2--2242 designs.
  • unityole - Wednesday, December 28, 2016 - link

    people like you only look at sequential eh? know why SSD is so much faster than HDD? its because of latency hence the QD1 4k random read/write performance. optane will bring QD1 4k random read/write so much closer to that speed of ram, samsung isnt even able to compete. the sequential speed you see won't be used as often as you think brother.

    time to move on and really learn what tech is about and what benefits and what doesn't.

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