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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YazX_ - Monday, April 24, 2017 - link
"Since our Optane Memory sample died after only about a day of testing"LOL
Chaitanya - Monday, April 24, 2017 - link
And it is supposed to have endurance rating 21x larger than a conventional NAND SSD.Sarah Terra - Monday, April 24, 2017 - link
Funny yes, but teething issues aside the random write Performance is several orders of magnitude faster than all existing storage mediums, this is the number one metric I find that plays into system responsiveness, boot times, and overall performance and the most ignored metric by all Meg's to date. They all go for sequential numbers, which don't mean jack except when doing large file copies.ddriver - Monday, April 24, 2017 - link
So let's summarize:1000 times faster than NAND - in reality only about 10x faster in hypetane's few strongest points, 2-6x better in most others, maximum thorough lower than consumer NVME SSDs, intel lied about speed about 200 times LOL. Also from Tom's review, it became apparent that until the cache of comparable enterprise SSDs fills up, they are just as fast as hypetane, which only further solidifes my claim that xpoint is NO BETTER THAN SLC, because that's what those drives use for cache.
1000 times the endurance of flash - in reality like 2-3x better than MLC. Probably on par with SLC at the same production node. Intel liked about 300-500 times.
10 times denser than flash - in reality it looks like density is actually way lower than. 400 gigs in what.. like 14 chips was it? Samsung has planar flash (no 3d) that has more capacity in a single chip.
So now they step forward to offer this "flash killer" as a puny 32 gb "accelerator" which makes barely any to none improvement whatsoever and cannot even make it through one day of testing.
That's quite exciting. I am actually surprised they brought the lowest capacity 960 evo rather than the p600.
Consumer grade software already sees no improvement whatsoever from going sata to nvme. It won't be any different for hypetane. Latency are low queue depth access is good, but that's mostly the controller here, in this aspect NAND SSDs have a tremendous headroom for improvement. Which is what we are most likely going to see in the next generation from enterprise products, obviously it makes zero sense for consumers, regardless of how "excited" them fanboys are to load their gaming machines with terabytes of hypetane.
Last but not least - being exclusive to intel's latest chips is another huge MEH. Hypetane's value is already low enough at the current price and limited capacity, the last thing that will help adoption is having to buy a low value intel platform for it, when ryzen is available and offers double the value of intel offerings.
Drumsticks - Monday, April 24, 2017 - link
Your bias is showing.1000x -> Harp on it all you want, but that number was for the architecture not the first generation end product. It represents where we can go, not where we are. I'll also note that Toms gave it their editor approved award - "As tested today with mainstream settings, Optane Memory performed as advertised. We observed increased performance with both a hard disk drive and an entry-level NVMe SSD. The value proposition for a hard drive paired with Optane Memory is undeniable. The combination is very powerful, and for many users, a better solution than a larger SSD."
"1000 times the endurance of flash -> You can concede that 3D XPoint density isn't as good as they originally envisioned, but it's still impressive, gen1, and has nowhere to go but up. It's not really worse than other competing drives per drive capacity - this cache supports like 3 DWPD basically. The MX300 750GB only supports like .3 DWPD. 10x better is still good.
10 times denser than flash -> DRAM, not Flash. And it's going to be much denser than DRAM.
Barely any to no improvement -> LOL, did you look at the graphs? Those lines at the bottom and on the left were 500GB and 250GB Sata and NVMe drives getting killed by Optane in a 32GB configuration. 3D XPoint was designed for low queue depth and random performance - i.e. things that actually matter, where it kills its competition. Even sequential throughput, which is far from its design intention, generally outperforms consumer drives.
So, Optane costs, in an enterprise SSD, 2-3x more than other enterprise drives, for record breaking low queue depth throughput that far surpasses its extra cost, while providing 10-80x less latency. In a consumer drive, Optane regularly approaches an order of magnitude faster than consumer drives in only a 32GB configuration.
If Optane is only as fast as SLC, I'd love to understand why the P4800X broke records as pretty much the fastest drive in the world, barring unrealistically high queue depths.
This 32GB cache might be a stopgap, and less compelling of a product in general because of its capacity, but that you could deny the potential that 3D XPoint holds is absolutely laughable. The random performance and low queue depth performance is undeniably better than NAND, and that's where consumer performance matters.
ddriver - Monday, April 24, 2017 - link
"I'd love to understand why the P4800X broke records"Because nobody bothered to make a SLC drive for many many years. The last time there were purely SLC drives on the market it was years ago, with controllers completely outdated compared to contemporary standards.
SLC is so good that today they only use it for cache in MLC and TLC drives. Kinda like what intel is trying to push hypetane as. Which is why you can see SSDs hitting hypetane IOPs with inferior controllers, until they run out of SLC cache space and performance plummets due to direct MLC/TLC access.
I bet my right testicle that with a comparable controller, SLC can do as well and even better than hypetane. SLC PE latencies are in the low hundreds of NANOseconds, which is substantially lower than what we see from hypetane. Endurance at 40 nm is rated at 100k PE cycles, which is 3 times more than what hypetane has to offer. It will probably drop as process node shrinks but still.
"10x better is still good"
Yet the difference between 10x and 1000x is 100x. Like imagine your employer tells you he's gonna pay you 100k a year, and ends up paying you a 1000 bucks instead. Surely not something anyone would object to LOL.
I am not having problems with "10x better". I am having problems with the fact it is 100x less than what they claimed. Did they fail to meet their expectations, or did they simply lie?
I am not denying hypetane's "potential". I merely make note that it is nothing radically better than nand flash that has not been compromised for the sake of profit. xpoint is no better than SLC nand. With the right controller, good old, even ancient and almost forgotten SLC is just as good as intel and micron's overhyped love child. Which is kinda like reinventing the wheel a few thousand years later, just to sell it at a few times what its actually worth.
My bias is showing? Nope, your "intel inside" underpants are ;)
Reflex - Monday, April 24, 2017 - link
SLC has severe limits on density and cost. It's not used because of that. Even at the same capacity as these initial Optane drives it would likely cost considerably more, and as Optane's density increases there is no ability to mitigate that cost with SLC, it would grow linearly with the amount of flash. The primary mitigations already exists: MLC and TLC. Of course those reduce the performance profile far below Optane and decrease it's ability to handle wear. Technically SLC could go with a stacked die approach, as MLC/TLC are doing, however nothing really stops Optane from doing the same making that at best a neutral comparison.ddriver - Monday, April 24, 2017 - link
SLC is half the density of MLC. Samsung has 2 TB of MLC worth in 4 flash chips. Gotta love 3D stacking. Now employ epic math skills and multiply 4 by 0.5, and you get a full TB of SLC goodness, perfectly doable via 3D stacked nand.And even if you put 3D stacking aside, which if I am not mistaken the sm961 uses planar MLC, 2 chips on each side for a full 1 TB. Cut that in half, you'd get 512 GB of planar SLC in 4 modules.
Now, I don't claim to be that good in math, but if you can have 512 GB of SLC nand in 4 chips, and it takes 14 for a 400 GB of xpoint, that would make planar SLC OVER 4 times denser than xpoint.
Thus if at planar dies SLC is over 4 times better, stacked xpoint could not possibly not possibly be better than stacked SLC.
Severe limits my ass. The only factor at play here is that SSDs are already faster than needed in 99% of the applications. Thus the industry would rather churn MLC and TLC to maximize the profit per grain of sand being used. The moment hypetane begins to take market share, which is not likely, they can immediately launch SLC enterprise products.
Also, it should be noted that there is still ZERO information about what the xpoint medium actually is. For all we know, it may well be SLC, now wouldn't that be a blast. Intel has made a bunch of claims about it, none of which seemed plausible, and most of which have already turned out to be a lie.
ddriver - Monday, April 24, 2017 - link
*multiply 2 by 0.5Reflex - Monday, April 24, 2017 - link
You can 3D stack Optane as well. That's a wash. You seem very obsessed with being right, and not with understanding the technology.