The Intel Optane Memory (SSD) Preview: 32GB of Kaby Lake Cachingby Billy Tallis on April 24, 2017 12:00 PM EST
- Posted in
- PCIe SSD
- SSD Caching
- 3D XPoint
- Optane Memory
Last week, we took a look at Intel's first product based on their 3D XPoint non-volatile memory technology: the Optane SSD DC P4800X, a record-breaking flagship enterprise SSD. Today Intel launches the first consumer product under the Optane brand: the Intel Optane Memory, a far smaller device with a price that is 20 times cheaper. Despite having "Memory" in its name, this consumer Optane Memory product is not a NVDIMM nor is it in any other way a replacement for DRAM (those products will be coming to the enterprise market next year, even though the obvious name is now taken). Optane Memory also not a suitable replacement for mainstream flash-based SSDs, because Optane Memory is only available in 16GB and 32GB capacities. Instead, Optane Memory is Intel's latest attempt at an old idea that is great in theory but has struggled to catch on in practice: SSD caching.
Optane is Intel's brand name for products based on the 3D XPoint memory technology they co-developed with Micron. 3D XPoint is a new class of non-volatile memory that is not a variant of flash memory, the current mainstream technology for solid state drives. NAND flash memory—be it older planar NAND or newer 3D NAND flash—has fundamental limits to performance and write endurance, and many of the problems get worse as flash is shrunk to higher densities. 3D XPoint memory takes a radically different approach to non-volatile storage, and it makes different tradeoffs between density, performance, endurance and cost. Intel's initial announcement of 3D XPoint memory technology in 2015 came with general order of magnitude comparisons against existing memory technologies (DRAM and flash). Compared to NAND flash, 3D XPoint is supposed to be on the order of 1000x faster with 1000x higher write endurance. Compared to DRAM, 3D XPoint memory is supposed to be about 10x denser, which generally implies it'll be cheaper per GB by about the same amount. Those comparisons were about the raw memory itself and not about the performance of an entire SSD, and they were also projections based on memory that was still more than a year from hitting the market.
3D XPoint memory is not intended or expected to be a complete replacement for flash memory or DRAM in the foreseeable future. It offers substantially lower latency than flash memory but at a much higher price per GB. It still has finite endurance that makes it unsuitable as a drop-in replacement for DRAM without some form of wear-leveling. The natural role for 3D XPoint technology seems to be as a new tier in the memory hierarchy, slotting in between the smaller but faster DRAM and the larger but slower NAND flash. The Optane products released this month are using the first-generation 3D XPoint memory, along with first-generation controllers. Future generations should be able to offer substantial improvements to performance, endurance and capacity, but it's too soon to tell how those characteristics will scale.
The Intel Optane Memory is a M.2 NVMe SSD using 3D XPoint memory instead of NAND flash memory. 3D XPoint allows the Optane Memory to deliver far higher throughput than any flash SSD of equivalent capacity, and lower read latency than a NAND flash SSD of any capacity. The Optane Memory is intended both for OEMs to integrate into new systems and as an aftermarket upgrade for "Optane Memory ready" systems: those that meet the system requirements for Intel's new Optane caching software and have motherboard firmware support for booting from a cached volume. However, the Optane Memory can also be treated as a small and fast NVMe SSD, because all of the work to enable its caching role is performed in software or by the PCH on the motherboard. 32GB is even (barely) enough to be used as a Windows boot drive, though doing so would not be useful for most consumers.
Intel Optane Memory uses a PCIe 3.0 x2 link, while most M.2 PCIe SSDs use the full 4 lanes the connector is capable of. The two-lane link allows the Optane Memory to use the same B and M connector key positions that are used by M.2 SATA SSDs, so there's no immediate visual giveaway that Optane Memory requires PCIe connectivity from the M.2 socket. The Optane Memory is a standard 22x80mm single-sided card but the components don't come close to using the full length. The controller chip is far smaller than a typical NVMe SSD controller, and the Optane Memory includes just one or two single-die packages of 3D XPoint memory. The Optane Memory module has labels on the front and back that contain a copper foil heatspreader layer, positioned to cool the memory rather than the controller. There is no DRAM visible on the drive.
|Intel Optane Memory Specifications|
|Capacity||16 GB||32 GB|
|Form Factor||M.2 2280 B+M key|
|Interface||PCIe 3.0 x2|
|Memory||128Gb 20nm Intel 3D XPoint|
|Sequential Read||900 MB/s||1350 MB/s|
|Sequential Write||145 MB/s||290 MB/s|
|Random Read||190k IOPS||240k IOPS|
|Random Write||35k IOPS||65k IOPS|
|Read Latency||7µs||9 µs|
|Write Latency||18µs||30 µs|
|Active Power||3.5 W||3.5 W|
|Idle Power||1 W||1 W|
|Endurance||182.5 TB||182.5 TB|
The performance specifications of Intel Optane Memory have been revised slightly since the announcement last month, with Intel now providing separate performance specs for the two capacities. Given the PCIe x2 link it's no surprise to see that sequential read speeds are substantially lower than we see from other NVMe SSDs, with 900 MB/s for the 16GB model and 1350 MB/s for the 32GB model. Sequential writes of 145 MB/s and 290 MB/s are far slower than consumer SSDs are usually willing to advertise, but are typical of the actual sustained sequential write speed of a good TLC NAND SSD. Random read throughput of 190k and 240k IOPS is in the ballpark for other NVMe SSDs. Random write throughput of 35k and 65k IOPS are also below the peak speeds advertised my most consumer SSDs, but on par with mainstream TLC and MLC SSDs respectively for actual performance at low queue depths.
Really it's the latency specifications where Optane Memory shines: the read latency of 7µs and 9µs for the 16GB and 32GB respectively are slightly better than even the enterprise Optane SSD DC P4800x, while write latency of 18µs and 30µs are just 2-3 times slower. The read latencies are completely untouchable for flash-based SSDs, but the write latencies can be matched by other NVMe controllers, but only because they cache write operations instead of performing them immediately.
The power consumption and endurance specifications don't look as impressive. 3.5W active power is lower than many M.2 PCIe SSDs and low enough that thermal throttling is unlikely to be a problem. The 1W idle power is unappealing, if not a bit problematic. Many M.2 NVMe SSDs will idle at 1W or more if the system is not using PCIe Active State Power Management and NVMe Power States. The Optane Memory doesn't even support the latter and will apparently draw the full 1W even in a well-tuned laptop. Since these power consumption numbers are typically going to be in addition to the power consumption of a mechanical hard drive, an Optane caching configuration is not going to offer decent power efficiency.
Meanwhile write endurance is rated at the same 100GB/day or 182.5 TB total for both capacities. Even though a stress test could burn through all of that in a week or two, 100GB/day is usually plenty for ordinary consumer use. However, a cache drive will likely experience a higher than normal write load as data and applications will tend to get evicted from the cache only to be pulled back in the next time they are loaded. More importantly, Intel promised that 3D XPoint would have on the order of 1000x the endurance of NAND flash, which should put these drives beyond the write endurance of any other consumer SSDs even after accounting for their small capacity.
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ddriver - Tuesday, April 25, 2017 - linkYeah, daring intel, the pioneer, taking mankind to better places.
Oh wait, that's right, it is actually a greedy monopoly that has mercilessly milked people while making nothing aside from barely incremental stuff for years and through its anti-competitive practices has actually held progress back tremendously.
As I already mentioned above, the last time "intel dared to innovate" that resulted in netburst. Which was so bad that in order to save the day intel had to... do what? Innovate once again? Nope, god forbid, what they did was go back and improve on the good design they had and scrapped in their futile attempts to innovate.
And as I already mentioned above, all the secrecy behind xpoint might be exactly because it is NOTHING innovative, but something old and forgotten, just slightly improved.
Reflex - Tuesday, April 25, 2017 - linkAxe is looking pretty worn down from all that grinding....
ddriver - Wednesday, April 26, 2017 - linkAlso, unlike you, I don't let personal preferences cloud my objectivity. If a product is good, even if made by the most wretched corporation out there, it is not a bad product just because of who makes it, it is still a good product, still made by a wretched corporation.
Even if intel wasn't a lousy bloated lazy greedy monopolist, hypetane would still suck, because it isn't anywhere near the "1000x" improvements they promised. It would suck even if intel was a charity that fed the starving in the 3rd world.
I would have had ZERO objections to hypetane, and also wouldn't call it hypetane to begin with, if intel, the spoiled greedy monopolist was still decent enough to not SHAMELESSLY LIE ABOUT IT.
Had they just said "10x better latency, 4x better low depth queue performance" and stuff like that, I'd be like "well, it's ok, it is faster than nand, you delivered what you promised.
But they didn't. They lied, and lied, and now that it is clear that they lied, they keep on lying and smearing with biased reviews in unrealistic workloads.
What kind of an idiot would ever approve of that?
fallaha56 - Tuesday, April 25, 2017 - linkOMG when our product wasn't as good as we said it was we didn't own-up about it
and maybe you test against HDD (like Intel) but the rest of us are already packing SSDs
philehidiot - Saturday, April 29, 2017 - linkThis is what companies do. Your technology is useless unless you can market it. And you don't market anything by saying it's mediocre. Look at BP's high octane fuel which supposedly cleans your engine and gets better fuel efficiency. The ONLY thing that higher octane fuel does is resist auto-ignition under compression better and thus certain high performance engines require it. As for cleaning your engine - you're telling me you've got a solvent which is better at cutting through crap than petrol AND can survive the massive temperatures and pressures inside the combustion chamber? It's the petrol which scrubs off the crap so yes, it's technically true. They might throw and additive or two in there but that will only help pre-combustion chamber and if you actually have a problem. And Yes, in certain, newer cars with certain sensors you will get SLIGHTLY higher MPG and therefore they advertise the maximum you'll get under ideal conditions because no one will but into it if you're realistic about the gains. The gains will never offset the extra cost of the fuel, however.
PC marketing is exactly the same and why the J Micron controller was such a disaster so many years ago. They went for advertised high sequential throughput numbers being as high as possible and destroyed the random performance, Anand spotted it and OCZ threw a wobbler. But that experience led to drives being advertised on random performance as well as sequential.
So what's the lesson here? We should always take manufacturer's claims with a mouthful of salt and buy based on objective criteria and independent measurements. Manufacturers will always state what is achievable in basically a lab set up with conditions controlled to perfection. Why? Because for one you can't quote numbers based on real life performance because everyone's experience will differ and you can't account for the different variables they'll experience. And for two, if everyone else is quoting the maximum theoretical potential, you're immediately putting yourself at a disadvantage by not doing so yourself. It's not about your product, it's about how well you can sell it to a customer - see: Stupidly expensive Dyson Hairdryer. Provides no real performance benefit over a cheap hairdryer but cost a lot in R&D and is mostly advertising wank for rich people with small brains.
As for Intel being a greedy monopoly... welcome to capitalism. If you don't want that side effect of the system then bugger off to Cuba. Capitalism has brought society to the highest standard of living ever seen on this planet. No other form of economic operation has allowed so many to have so much. But the result is big companies like Intel, Google, Apple, etc, etc.
Advertising wank is just that. Figures to masturbate over. If they didn't do it then sites like Anandtech wouldn't need to exist as products would always be accurately described by the manufacturer and placed honestly within the market and so reviews wouldn't be required.
I doubt they lied completely - they will be going on the theoretical limits of their technology when all engineering limitations are removed. This will never happen in practice and will certainly never happen in a gen 1 product. Also, whilst I see this product as being pointless, it's obviously just a toe dipping exercise like the enterprise model. Small scale, very controlled use cases and therefore good real world use data to be returned for gen 2/3.
Personally, whilst I'm wowed by the figures, I don't see how they're going to improve things for me. So what's the point in a different technology when SLC can probably perform just as well? It's a different development path which will encounter different limitations and as a result will provide different advantages further down the road. Why do they continue to build coal fired power stations when we have CCGTs, wind, solar, nukes, etc? Because each technology has its strengths and weaknesses and encounters different engineering limitations in development. Plus a plurality of different, competing technologies is always better as it creates progress. You can't whinge about monopolies and then when someone starts doing something different and competing with the established norm start whinging about that.
fallaha56 - Tuesday, April 25, 2017 - linkhi @sarah i find that a dead hard drive also plays into responsiveness and boot times(!)
this technology is clearly not anywhere near as good as Intel implied it was
CaedenV - Monday, April 24, 2017 - linkI have never once had an SSD fail because it has over-used its flash memory... but controllers die all the time. It seems that this will remain true for this as well.
Ryan Smith - Tuesday, April 25, 2017 - linkAnd that's exactly what we're suspecting here. We've likely managed to hit a bug in the controller's firmware. Which to be sure, isn't fantastic, but it can be fixed.
Prior to the P3700's launch, Intel sent us 4 samples specifically for stress testing. We managed to disable every last one of them. However Intel learned from our abuse, and now those same P3700s are rock-solid thanks to better firmware and drivers.
jimjamjamie - Tuesday, April 25, 2017 - linkInteresting that an ad-supported website can stress-test better than a multi-billion dollar company..
testbug00 - Tuesday, April 25, 2017 - linkbased on what? Have they sent you another model?
A sample dying on day one, and only allowing testing via remote server doesn't confidence build.