Introduction, How PCM Works, Reading, Writing, and Tweaks

I’ve seen a bit of flawed logic floating around related to discussions about 3D XPoint technology. Some are directly comparing the cost per die to NAND flash (you can’t - 3D XPoint likely has fewer fab steps than NAND - especially when compared with 3D NAND). Others are repeating a bunch of terminology and element names without taking the time to actually explain how it works, and far too many folks out there can't even pronounce it correctly (it's spoken 'cross-point'). My plan is to address as much of the confusion as I can with this article, and I hope you walk away understanding how XPoint and its underlying technologies (most likely) work. While we do not have absolute confirmation of the precise material compositions, there is a significant amount of evidence pointing to one particular set of technologies. With Optane Memory now out in the wild and purchasable by folks wielding electron microscopes and mass spectrometers, I have seen enough additional information come across to assume XPoint is, in fact, PCM based.

XPoint.png

XPoint memory. Note the shape of the cell/selector structure. This will be significant later.

While we were initially told at the XPoint announcement event Q&A that the technology was not phase change based, there is overwhelming evidence to the contrary, and it is likely that Intel did not want to let the cat out of the bag too early. The funny thing about that is that both Intel and Micron were briefing on PCM-based memory developments five years earlier, and nearly everything about those briefings lines up perfectly with what appears to have ended up in the XPoint that we have today.

comparison.png

Some die-level performance characteristics of various memory types. source

The above figures were sourced from a 2011 paper and may be a bit dated, but they do a good job putting some actual numbers with the die-level performance of the various solid state memory technologies. We can also see where the ~1000x speed and ~1000x endurance comparisons with XPoint to NAND Flash came from. Now, of course, those performance characteristics do not directly translate to the performance of a complete SSD package containing those dies. Controller overhead and management must take their respective cuts, as is shown with the performance of the first generation XPoint SSD we saw come out of Intel:

gap.png

The ‘bridging the gap’ Latency Percentile graph from our Intel SSD DC P4800X review.
(The P4800X comes in at 10us above).

There have been a few very vocal folks out there chanting 'not good enough', without the basic understanding that the first publicly available iteration of a new technology never represents its ultimate performance capabilities. It took NAND flash decades to make it into usable SSDs, and another decade before climbing to the performance levels we enjoy today. Time will tell if this holds true for XPoint, but given Micron's demos and our own observed performance of Intel's P4800X and Optane Memory SSDs, I'd argue that it is most certainly off to a good start!

XPoint Die.jpg

A 3D XPoint die, submitted for your viewing pleasure (click for larger version).

You want to know how this stuff works, right? Read on to find out!

Podcast #447 - Intel Optane, Watercooling, Mini ITX AM4, and Intel Optane

Subject: Editorial | April 27, 2017 - 12:19 PM |
Tagged: podcast, Win 3.11, ssd, riotoro, Optane Memory, Optane, Intel, GTX 1080Ti, fsp, evga, EK Supremacy, corsair, biostar, asus, video

PC Perspective Podcast #447 - 04/27/17

Join us for loads of Intel Optane, multiple water cooling parts, a Mini-ITX AM4 board, and more!

You can subscribe to us through iTunes and you can still access it directly through the RSS page HERE.

The URL for the podcast is: http://pcper.com/podcast - Share with your friends!

Hosts: Jeremy Hellstrom, Allyn Malventano, Ken Addison, Morry Teitelman

Peanut Gallery: Alex Lustenberg

Program length: 1:50:22

Podcast topics of discussion:
  1. Week in Review:
  2. News items of interest:
  3. Hardware/Software Picks of the Week
    1. Allyn: Factorio fans - 0.15 experimental is out! (new graphics)(dev test img)
    2. Morry: Bayonetta
  4. Closing/outro

 

 

Source:

Spent all your money on a new CPU and couldn't afford an SSD? Intel Optane Memory is here

Subject: Storage | April 24, 2017 - 05:20 PM |
Tagged: XPoint, srt, rst, Optane Memory, Optane, Intel, hybrid, CrossPoint, cache, 32GB, 16GB

At $44 for 16GB or $77 for a 32GB module Intel's Optane memory will cost you less in total for an M.2 SSD, though a significantly higher price per gigabyte.  The catch is that you need to have a Kaby Lake Core system to be able to utilize Optane, which means you are unlikely to be using a HDD.  Al's test show that Optane will also benefit a system using an SSD, reducing latency noticeably although not as significantly as with a HDD.

The Tech Report tested it differently, by sourcing a brand new desktop system with Kaby Lake Core APU that did not ship with an SSD.  Once installed, the Optane drive enabled the system to outpace an affordable 480GB SSD in some scenarios; very impressive for a HDD.  They also did peek at the difference Optane makes when paired with aforementioned affordable SSD in their full review.

requirements.png

"Intel's Optane Memory tech purports to offer most of the responsiveness of an SSD to systems whose primary storage device is a good old hard drive. We put a 32GB stick of Optane Memory to the test to see whether it lives up to Intel's claims."

Here are some more Storage reviews from around the web:

Storage

 

Subject: Storage
Manufacturer: Intel

Introduction, Specifications, and Requirements

Introduction:

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Finally! Optane Memory sitting in our lab! Sure, it’s not the mighty P4800X we remotely tested over the past month, but this is right here, sitting on my desk. It’s shipping, too, meaning it could be sitting on your desk (or more importantly, in your PC) in just a matter of days.

Intel-3D-Xpoint.png

The big deal about Optane is that it uses XPoint Memory, which has fast-as-lightning (faster, actually) response times of less than 10 microseconds. Compare this to the fastest modern NAND flash at ~90 microseconds, and the differences are going to add up fast. What’s wonderful about these response times is that they still hold true even when scaling an Optane product all the way down to just one or two dies of storage capacity. When you consider that managing fewer dies means less work for the controller, we can see latencies fall even further in some cases (as we will see later).

Read on for our full review of Optane Memory!

Subject: Storage
Manufacturer: Intel

Introduction and Specifications

Introduction

Intel-3D-Xpoint.png

XPoint. Optane. QuantX. We've been hearing these terms thrown around for two years now. A form of 3D stackable non-volatile memory that promised 10x the density of DRAM and 1000x the speed and endurance of NAND. These were bold statements, and over the following months, we would see them misunderstood and misconstrued by many in the industry. These misconceptions were further amplified by some poor demo choices on the part of Intel (fortunately countered by some better choices made by Micron). Fortunately cooler heads prevailed as Jim Handy and other industry analysts helped explain that a 1000x improvement at the die level does not translate to the same improvement at the device level, especially when the first round of devices must comply with what will soon become a legacy method of connecting a persistent storage device to a PC.

Did I just suggest that PCIe 3.0 and the NVMe protocol - developed just for high-speed storage, is already legacy tech? Well, sorta.

ss-142.png

That 'Future NVM' bar at the bottom of that chart there was a 2-year old prototype iteration of what is now Optane. Note that while NVMe was able to shrink down the yellow bar a bit, as you introduce faster and faster storage, the rest of the equation (meaning software, including the OS kernel) starts to have a larger and larger impact on limiting the ultimate speed of the device.

800px-Nand_flash_structure.svg_.png

NAND Flash simplified schematic (via Wikipedia)

Before getting into the first retail product to push all of these links in the storage chain to the limit, let's explain how XPoint works and what makes it faster. Taking random writes as an example, NAND Flash (above) must program cells in pages and erase cells in blocks. As modern flash has increased in capacity, the sizes of those pages and blocks have scaled up roughly proportionally. At present day we are at pages >4KB and block sizes in the megabytes. When it comes to randomly writing to an already full section of flash, simply changing the contents of one byte on one page requires the clearing and rewriting of the entire block. The difference between what you wanted to write and what the flash had to rewrite to accomplish that operation is called the write amplification factor. It's something that must be dealt with when it comes to flash memory management, but for XPoint it is a completely different story:

reading_bits_in_crosspoint_array.jpg

XPoint is bit addressible. The 'cross' structure means you can select very small groups of data via Wordlines, with the ultimate selection resolving down to a single bit.

ss-141.png

Since the programmed element effectively acts as a resistor, its output is read directly and quickly. Even better - none of that write amplification nonsense mentioned above applies here at all. There are no pages or blocks. If you want to write a byte, go ahead. Even better is that the bits can be changed regardless of their former state, meaning no erase or clear cycle must take place before writing - you just overwrite directly over what was previously stored. Is that 1000x faster / 1000x more write endurance than NAND thing starting to make more sense now?

Ok, with all of the background out of the way, let's get into the meat of the story. I present the P4800X:

P4800X.jpg

Read on for our full review of the P4800X!

Podcast #443 - Thermoelectric Coolers, Storage Reviews, and a StarCraft Remaster. oh my.

Subject: Editorial | March 30, 2017 - 10:40 AM |
Tagged: starcraft, Silverstone, Samsung, podcast, Phonoic, Optane, microSD, Lexar, HEX 2.0, drobo, CORSAIR ONE, ashes of the singularity, aida64, 5N2

PC Perspective Podcast #443 - 03/30/17

Join us for Thermoelectric Coolers, Tiny PSUs, Lots o' Storage, some trips down nostaglia lane, and more!

You can subscribe to us through iTunes and you can still access it directly through the RSS page HERE.

The URL for the podcast is: http://pcper.com/podcast - Share with your friends!

Hosts: Ryan Shrout, Jeremy Hellstrom, Josh Walrath, Allyn Malventano

Program length: 1:34:48

 

Source:

Intel Officially Launches Optane Memory, Shows Performance

Subject: Storage | March 27, 2017 - 12:16 PM |
Tagged: XPoint, Optane Memory, Optane, M.2, Intel, cache, 3D XPoint

We are just about to hit two years since Intel and Micron jointly launched 3D XPoint, and there have certainly been a lot of stories about it since. Intel officially launched the P4800X last week, and this week they are officially launching Optane Memory. The base level information about Optane Memory is mostly unchanged, however, we do have a slide deck we are allowed to pick from to point out some of the things we can look forward to once the new tech starts hitting devices you can own.

Optane Memory-6.png

Alright, so this is Optane Memory in a nutshell. Put some XPoint memory on an M.2 form factor device, leverage Intel's SRT caching tech, and you get a 16GB or 32GB cache laid over your system's primary HDD.

Optane Memory-15.png

To help explain what good Optane can do for typical desktop workloads, first we need to dig into Queue Depths a bit. Above are some examples of the typical QD various desktop applications run at. This data is from direct IO trace captures of systems in actual use. Now that we've established that the majority of desktop workloads operate at very low Queue Depths (<= 4), lets see where Optane performance falls relative to other storage technologies:

Optane Memory-22.png

There's a bit to digest in this chart, but let me walk you through it. The ranges tapering off show the percentage of IOs falling at the various Queue Depths, while the green, red, and orange lines ramping up to higher IOPS (right axis) show relative SSD performance at those same Queue Depths. The key to Optane's performance benefit here is that it can ramp up to full performance at very low QD's, while the other NAND-based parts require significantly higher parallel requests to achieve full rated performance. This is what will ultimately lead to a much snappier responsiveness for, well, just about anything hitting the storage. Fun fact - there is actually a HDD on that chart. It's the yellow line that you might have mistook as the horizontal axis :).

Optane Memory-11.png

As you can see, we have a few integrators on board already. Official support requires a 270 series motherboard and Kaby Lake CPU, but it is possible that motherboard makers could backport the required NVMe v1.1 and Intel RST 15.5 requirements into older systems.

Optane Memory-7.png

For those curious, if caching is the only way power users will be able to go with Optane, that's not the case. Atop that pyramid there sits an 'Intel Optane SSD', which should basically be a consumer version of the P4800X. It is sure to be an incredibly fast SSD, but that performance will most definitely come at a price!

We should be testing Optane Memory shortly and will finally have some publishable results of this new tech as soon as we can!

Source: Intel

Podcast #442 - ARM DynamIQ, Optane Launch, Gigabit LTE, Vulkan

Subject: Editorial | March 23, 2017 - 12:26 PM |
Tagged: Yoga Book, vulkan, topre, snapdragon 835, SC17, qualcomm, podcast, Optane, LG 32UD99, Lenovo, Gigabit LTE, evga, DynamIQ, arm

PC Perspective Podcast #442 - 03/23/17

Join us for Topre and CORSAIR Keyboards, ARM DynamIQ, Optane Launch, EVGA 4K gaming laptop, and more!

You can subscribe to us through iTunes and you can still access it directly through the RSS page HERE.

The URL for the podcast is: http://pcper.com/podcast - Share with your friends!

Hosts: Ryan Shrout, Jeremy Hellstrom, Allyn Malventano, Ken Addison

Program length: 1:35:25

 

Source:

Intel Officially Kicks Off Optane Launch with SSD DC P4800X

Subject: Storage | March 19, 2017 - 12:21 PM |
Tagged: XPoint, SSD DC P4800X, Optane Memory, Optane, Intel, client, 750GB, 3D XPoint, 375GB, 1.5TB

Intel brought us out to their Folsom campus last week for some in-depth product briefings. Much of our briefing is still under embargo, but the portion that officially lifts this morning is the SSD DC P4800X:

Intel_SSD_4800_FlatFront_OnWhite_RGB_Small.jpg

optane-4.png

optane-9.png

MSRP for the 375GB model is estimated at $1520 ($4/GB), which is rather spendy, but given that the product has shown it can effectively displace RAM in servers, we should be comparing the cost/GB with DRAM and not NAND. It should also be noted this is also nearly half the cost/GB of the X25-M at its launch. Capacities will go all the way up to 1.5TB, and U.2 form factor versions are also on the way.

For those wanting a bit more technical info, the P4800X uses a 7-channel controller, with the 375GB model having 4 dies per channel (28 total). Overprovisioning does not do for Optane what it did for NAND flash, as XPoint can be rewritten at the byte level and does not need to be programmed in (KB) pages and erased in larger (MB) blocks. The only extra space on Optane SSDs is for ECC, firmware, and a small spare area to map out any failed cells.

Those with a keen eye (and calculator) might have noted that the early TBW values only put the P4800X at 30 DWPD for a 3-year period. At the event, Intel confirmed that they anticipate the P4800X to qualify at that same 30 DWPD for a 5-year period by the time volume shipment occurs.

Read on for more about the SSD DC P4800X (and other upcoming products!)

Intel Details Optane Memory System Requirements

Subject: General Tech, Storage | February 21, 2017 - 07:14 PM |
Tagged: Optane, kaby lake, Intel, 3D XPoint

Intel has announced that its Optane memory will require an Intel Kaby Lake processor to function. While previous demonstrations of the technology used an Intel Skylake processor, it appears this configuration will not be possible on the consumer versions of the technology.

Intel Optane App Accelerator.jpg

Further, the consumer application accelerator drives will also require a 200-series chipset motherboard, and either a M.2 2280-S1-B-M or M.2 2242-S1-B-M connector with two or four PCI-E lanes. Motherboards will have to support NVMe v1.1 and Intel RST (Rapid Storage Technology) 15.5 or newer.

It is not clear why Intel is locking Optane technology to Kaby Lake and whether it is due to technical limitations that they were not able to resolve to keep Skylake compatible or if it is just a matter of not wanting to support the older platform and focus on its new Kaby Lake processors. As such, Kaby Lake is now required if you want UHD Blu Ray playback and Optane 3D XPoint SSDs.

What are your thoughts on this latest bit of Optane news? Has Intel sweetened the pot enough to encourage upgrade hold outs?

Also Read: 

 

Source: Bit-Tech