The Intel Optane Memory (SSD) Preview: 32GB of Kaby Lake Caching
by Billy Tallis on April 24, 2017 12:00 PM EST- Posted in
- SSDs
- Storage
- Intel
- PCIe SSD
- SSD Caching
- M.2
- NVMe
- 3D XPoint
- Optane
- Optane Memory
First Thoughts
Since our Optane Memory sample died after only about a day of testing, we cannot conduct a complete analysis of the product or make any final recommendations. With that said, the early indications from the benchmarks we were able to complete are mostly very positive reflections of the performance of the Intel Optane Memory.
As a cache device, the Optane Memory brought a hard drive-based system's SYSmark scores up to the level of mainstream SSDs. These averages do not capture differences in the latency distributions of the Optane cache+hard drive configuration vs a flash SSD. In the Optane+hard drive configuration, a cache hit will be almost 1000 times faster than a cache miss, resulting in a very bimodal distribution. The flash SSDs mostly occupy the territory between the performance of Optane and of the hard drive. It's possible that a mainstream flash SSD could deliver a user experience with fewer noticeable delays than the Optane caching experience with the occasional inevitable cache miss. Overall, however, the Optane cache delivers a remarkable improvement over just a hard drive, and the 32GB cache capacity we tested is clearly large enough to be of substantial use.
As a standalone drive, the Optane Memory breaks a few records that were set by the Intel Optane SSD DC P4800X enterprise drive just last week. The Optane Memory is more tuned for small transfer sizes and offers even better QD1 random read performance. These differences seem like exactly the right optimizations to make for a drive focused on client workloads. The throughput at higher queue depths is nowhere near what the P4800X delivers and falls behind what more expensive consumer SSDs can offer, but those situations make up a very small portion of client workloads. The first and only batch of synthetic tests we were able to run on the Optane Memory were derived from the enterprise SSD tests used on the Optane SSD DC P4800X, and they cast the consumer flash SSDs in an unrealistically bad light. A typical desktop user has little reason to care how well their SSD handles multiple threads performing sustained sequential transfers on a full drive, so the Optane Memory's stellar performance there should not lead users to prefer an Optane cached hard drive setup over an all solid state configuration.
The one area where we are ready to draw some conclusions is power consumption. We still need to conduct further analysis of the Optane Memory's power use under load, but its idle power situation is simple: the Optane Memory lacks any meaningful power saving mode. It is rated for 1W at idle and that's the lowest we saw it get throughout our short time testing it. 1W is something desktop users can shrug off; a typical gaming desktop dedicates more power than that to decorative LEDs. But Optane Memory is also intended for mobile use, and the first systems announced to offer Optane Memory were Lenovo ThinkPads. Adding a minimum of 1W on top of the power drawn by a mechanical hard drive will not help battery life, no matter how much faster it makes the storage system.
With Optane Memory, Intel seems to finally have the cache device they've been needing for a decade to make SSD caching viable. It's fast in spite of its low capacity, something flash based cache devices could never pull off. Optane Memory is also more affordable at $44 and $77 than Intel's previous cache devices.
With that said, however, I wonder whether it may all be too little, too late. SSD caching has some unavoidable limitations: cold caches, cache evictions when the cache proves too small, and the added complexity of a tiered setup. With those disadvantages, Optane Memory enters a market where the price of flash SSDs means there's already very little reason for consumer machines to use a mechanical hard drive as primary storage. Instead, the best case scenario here appears to be enabling the capacity benefits of tiered storage - offering nimble systems with 1TB+ of cheap storage and is presented to the user as a single drive - but without as many of the drawbacks of earlier NAND-based caches.
In some sense, Optane Memory may just be a stop-gap product for the consumer market until Intel is able to deliver usefully large Optane SSDs for consumers. But those SSDs are likely to arrive with prohibitively high prices if they ship later this year as planned. 3D XPoint memory has arrived and is poised to revolutionize parts of the enterprise storage market, but it may not be ready to have a meaningful impact on the consumer market.
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Billy Tallis - Wednesday, April 26, 2017 - link
As long as you have Intel RST RAID disabled for NVMe drives, it'll be accessible as a standard NVMe device and available for use with non-Intel caching software.fanofanand - Tuesday, April 25, 2017 - link
I came here to read ddriver's "hypetane" rants, and I was not disappointed!TallestJon96 - Tuesday, April 25, 2017 - link
Too bad about the drive breaking.As an enthusiast who is gaming 90% of the time with my pc, I don't think this is for me right now. I actually just bought a 960 evo 500gb to compliment my 1 tb 840 evo. Overkill for sure, but I'm happy with it, even if the difference is sometimes subtle.
This technology really excites me. If they can get a system running eith no Dram or Nand, and just use a large block of Xpoint, that could make for a really interesting system. Put 128 gb of this stuff paired with a 2c/4t mobile chip in a laptop, and you could get a really lean system that is fast for every day usage cases (web browsing, video watching, etc).
For my use case, I'd love to have a reason to buy it (no more loading times ever would be very futuristic) but it'll take time to really take off.
MrSpadge - Tuesday, April 25, 2017 - link
> no more loading timesNot going to happen, because there's quite some CPU work involved with loading things.
SanX - Tuesday, April 25, 2017 - link
Blahblahblah indurance, price, consumption, superspeed. Where they are? ROTFLOL At least don't show these shameful speeds if you opened your mouth this loud, Intel. No one will ever look at anything less then 3.5GB/s set by Samsung 960 Pro if you trolled about superspeeds.cheshirster - Wednesday, April 26, 2017 - link
Is there any technical reasoning why this won't work with older CPU's?I don't see this being any different than Intel RST.
KAlmquist - Thursday, April 27, 2017 - link
I think that Intel SRT caches reads, whereas the Optane Memory caches both reads and writes. My guess is that when Intel SRT places data in the cache, it doesn't immediately update the non-volatile lookup tables indicating where that data is stored. Instead, it probably waits until a bunch of data has been added, and then records the locations of all of the cached data. The reason for this would be that NAND can only be written in page units. If Intel were to update the non-volatile mapping table every time it added a page of data to the cache, that would double the amount of data written to the caching SSD.If I'm correct, then with Intel SRT, a power loss can cause some of the data in the SSD cache to be lost. The data itself would still be there, but it won't appear in the lookup table, making it inaccessible. That doesn't matter because SRT only caches reads, so the data lost from the cache will still be on the hard drive.
In contrast, Optane Memory memory presumably updates the mapping table for cached data immediately, taking advantage of the fact that it uses a memory technology that allows small writes. So if you perform a bunch of 4K random writes, the data is written to the Optane storage only, resulting in much higher write performance than you would get with Intel SRT.
In short, I would guess that Optane Memory uses a different caching algorithm than Intel SRT; an algorithm that is only implemented in Intel's latest chipsets.
That's unfortunate, because if Optane Memory were supported using software drivers only (without any chipset support), it would be a very attractive upgrade to older computer systems. At $44 or $77, an Optane Memory device is a lot less expensive than upgrading to an SSD. Instead, Optane Memory is targeted at new systems, where the economics are less compelling.
mkozakewich - Thursday, April 27, 2017 - link
I would really like to see the 16GB Optane filled with system paging file (on a device with 2 or 4 GB of RAM) and then do some general system experience tests. This seems like the perfect solution: The system is pretty good about offloading stuff that's not needed, and pulling needed files into working memory for full speed; and the memory can be offloaded to or loaded from the Optane cache quickly enough that it shouldn't cause many slowdowns when switching between tasks. This seems like the best strategy, in a world where we're still seeing 'pro' devices with 4 GB of RAM.Ugur - Monday, May 1, 2017 - link
I wish Intel would release Optane sticks/drives of 1-4TB sizes asap and sell them for 100-300 more than SSDS of same size immediately.I'm kinda disappointed they do this type of tiered rollout where it looks like it'll take ages until i can get an Optane drive at larger sizes for halfway reasonable prices.
Please Intel, make it available asap, i want to buy it.
Thanks =)
abufrejoval - Monday, May 8, 2017 - link
Well the most important thing is that Optane is now real a product on the market, for consumers and enterprise customers. So some Intel senior managers don’t need to get fired or cross off items on their bonus score cards.Marketing will convince the world that Optane is better, most importantly that only Intel can have it inside: No ARM, no Power no Zen based server shall ever have it.
For the DRAM-replacement variant, that exclusivity had a reason: Without proper firmware support, that won’t work and without special cache flushing instructions it would be too slow or still volatile.
Of course, all of that could be shared with the competition, but who want to give up a practical monopoly, which no competition can contest in court before their money runs out.
For the PCIe variant Intel, chipset and OS dependencies are all artificial, but doesn’t that make things better for everyone? Now people can give up ECC support in cheap Pentiums and instead gain Optane support for a premium on CPUs and chipsets, which use the very same hardware underneath for production cost efficiency. Whoever can sell that, truly deserves their bonus!
Actually, I’d propose they be paid in snake oil.
For the consumer with a linear link between Optane and its downstream storage tier, it means the storage path has twice as many opportunities to fail. For the service technician it means he has four times as many test scenarios to perform. Just think on how that will double again, once Optane does in fact also come to the DIMM socket! Moore’s law is not finished after all! Yeah!
Perhaps Microsoft could be talked into creating a special Optane Edition which offers much better granularity for forensic data storage, and surely there would be plenty of work for security researchers, who just love to find bugs really, really deep down in critical Intel Firmware, which is designed for the lowest Total Cost of TakeOwnership in the industry!
Where others see crisis, Intel creates opportunities!