Earlier this year, Intel and Micron's joint NAND manufacturing venture (IMFT) announced it had produced 64Gb (8GB) MLC NAND on a 20nm process. Most IMFT NAND that's used in SSDs are built using a 25nm process - the move to 20nm reduces die size and in turn reduces cost over time. A single 8GB 2-bit-per-cell MLC NAND die built on IMFT's 25nm process measures in at 167mm2, while the same capacity on IMFT's 20nm process is 118mm2. Early on in any new process wafers are more expensive, but over time NAND costs should go down as they are more a function of die size than process technology.

Today Intel and Micron are both announcing a second generation 20nm part at a 128Gb (16GB capacity). This isn't just a capacity increase as the 128Gb 20nm MLC NAND features an ONFi 3 interface rather than ONFI 2.x used in the earlier 64Gb announcement and older 25nm parts. ONFI 3 increases interface bandwidth from a max of 200MT/s (IMFT 25nm was limited to 166MT/s) to 333MT/s. This has a direct impact on sequential read performance for example, as most of those operations tend to be interface bound. Note that when I'm talking about interface speed I'm referring to the maximum speed allowed between the SSD controller and the NAND itself (e.g. an 8-channel ONFI 3 controller would have 8 x 333MT/s interfaces to NAND). 

Alongside the faster interface speed is yet another increase in page size. The move to 25nm NAND brought about 8KB pages (up from 4KB), the 128Gb 20nm MLC NAND solution uses 16KB pages. Because of the changes to the interface speed and page size we won't see drives/controllers use the 128Gb devices for another 1 - 1.5 years. The reason for the delay in incorporating this NAND into SSDs is two fold: 1) A 128Gb 20nm die will be pretty big (2x the size of a 64Gb die), and it'll take time for yields to improve to the point where it's cost effective, and 2) a larger page size and new interface both require a revision to the controller & firmware. Intel and Micron have both confirmed that they will not be using the 128Gb parts in SSDs until 2013.

The 128Gb 20nm parts will go into mass production in Q2 2012, giving IMFT ample time to ramp up production and work on yields before more functional deployment inside SSDs. SSD makers (and other consumers of NAND) will be able to get octal die packages using 128Gb NAND, meaning a single package can feature up to 128GB of NAND. This also paves the way for 1TB SSDs with only eight chips, or 2TB SSDs with both sides of a 2.5" PCB populated. The new Ultrabook/MacBook Air gumstick SSD form factor will be able to accommodate 512GB - 1TB of NAND using these 128Gb ODP devices.

While 128Gb parts are still some distance away, 64Gb 20nm NAND from IMFT is in mass production today.  Again, don't expect to see the 64Gb parts in use in SSDs until the middle of 2012 however. Controller vendors need time to ensure support for the NAND and validate/cross-their-fingers-and-hope-it-works with their designs. IMFT also needs time to build up inventory and ensure good yields. Remember the 64Gb parts retain the ONFI 2.x support and 8KB page size of IMFT's 25nm NAND.

The big question is endurance, however we won't see a reduction in write cycles this time around. IMFT's 20nm client-grade compute NAND (used in consumer SSDs) is designed for 3K - 5K write cycles, identical to its 25nm process. IMFT have moved to a new cell architecture with a much thinner floating gate. The 20nm process is also a high-K + metal gate design, both of which contribute to maintaining endurance ratings while shrinking overall transistor dimensions.

SSDs have fallen in prices tremendously over the past few years. We're finally approaching $1/GB in many cases. With 20nm NAND due out next year, I'd say we're probably within a year of dropping below $1/GB. 

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  • Exodite - Tuesday, December 6, 2011 - link

    Thing is, for most users you probably aren't far away from the truth.

    With the tasks most people use, mainly browsing, blogging, media consumption and minor editing, SSDs aren't really bringing much to the table.

    Especially in a time when people only reboot their computer when Windows Update tells them to.

    Heck, even as a fairly heavy user I struggle to motivate such purchases. Windows disk caching is, I'm astonished to say, quite good enough these days.

    And this is running a 5400RPM 'green' disk with AAM set to the most quiet level possible.

    There's no question that SSDs are an order of magnitude faster than HDDs, it's just rarely a real bottleneck.

    Then again tests have shown that human being start releasing stress hormones after waiting for one second so there's that... :)
  • Denithor - Tuesday, December 6, 2011 - link

    What's sad is, those are the very people that would benefit most from SSDs. Faster boots mean they don't have to wait around as long, reduced power consumption helps battery life (ok, so this is marginal, but basically useless on desktops).
  • Paul Tarnowski - Wednesday, December 7, 2011 - link

    I'd say it's exactly the opposite. Casual users are the perfect beneficiaries of an SSD.

    I just finished building an office where each computer has an SSD, with every computer backing up to a server twice daily. They benefit from faster response times to Excel, Word, Outlook, and the browser. That is nothing to sneeze at -- whereas before the receptionist might have launched Outlook and gone on a coffee break, now the system responds so fast she gets right to work. The only worry is failure rates, which is taken caring of by the twice daily backup. Regardless, I expect going back there to RMA one of the SSDs about as much as I do an HDD.

    The same benefits translate to mom and dad when the computer just runs what they want it to run with almost no lag. Especially now that Hotmail as well as Google offer decent online image storage, as well as external HDDs offer great space for the price.

    That's also why the iPad and other tablets are so popular -- they just work.

    It is computer "nerds" like us who have historically been willing to wait on processes. That's because have been, to a large extent, "addicted" enough that it doesn't matter how long we have to wait. It's after we have experience with first RAID-0 and now SSDs that we are unwilling to do so.
  • Paul Tarnowski - Wednesday, December 7, 2011 - link

    I should have written "upgrading an office". I did not, despite my vast reserves of awesome, actually build the office. That would be silly. I just upgraded the office computers and network. Overnight. By myself. In an office attached to a large, dark and cavernous shop floor. *

    I'll have troubleshooting nightmares for weeks.

    Also, "that's because have been" in the last paragraph should obviously be "that's because _we_ have been".

    * This is an exaggeration. It took more than just the one night.
  • stefmalawi - Tuesday, December 6, 2011 - link

    You're pretty much wrong on all counts there. The performance improvement both on paper and practically is to the extent that an SSD is the biggest improvement that one could make in the majority of systems out there.

    RAID is not for the typical consumer, especially RAID-0. In any case, even a RAID of HDD's would not perform nearly as well as a modern SSD, forgetting the fact that SSD's can in turn be RAIDED as well, negating your point and only proving even further improvement in performance in comparison to HDD's.

    Yes, they are more expensive. But especially in light of recent HDD price hikes, and the falling prices in SSD's, that's an advantage that will become negligible over time. As for today, SSD's are well within the price bracket for enthusiasts in particular, especially when you consider using multiple drives in a system (ie small SSD for boot/applications drive, HDD for storage like media. In this case even a 64Gb SSD is sufficient, and 128Gb is not unreasonably priced at all).

    SSD's from brands like Intel are for the most part more reliable than HDD's, especially 2.5'' HDD's (remember that SSD's are typically in a 2.5'' form factor). I do agree that there are quality assurance problems with some brands, and yes, Intel has had issues recently but for the most part you've picked the wrong brand entirely as an example of reliability concerns. Again this will hopefully be sorted out over time, look at OCZ's recent 180 in reliability, quality assurance, etc. Anand seems to regard their turn around pretty highly, and with their in house controller things will hopefully continue to improve.

    SSD's are going to be ubiquitous pretty soon, they are better than HDD's in all area's except price/Gb at the moment, and even that will change (yes, SSD's will eventually become cheaper than HDD's). For an enthusiast especially, and any consumers interested in aspects such as performance, reliability, noise, power consumption/heat (debatable atm), and size (read ultrabook) SSD's today are very desirable.
  • stefmalawi - Tuesday, December 6, 2011 - link

    ah whoops, just saw your reply. Forget my response then. In my defence however, your username didn't make the satire any more apparent!
  • kmmatney - Tuesday, December 6, 2011 - link

    The way things are going , the $/GB might be comparable soon!
  • robertgu2k - Tuesday, December 6, 2011 - link

    Wow...just wow....

    I admit I have not had my coffee yet, so my sarcasm detector might not be working fully yet. But where do I start? The only part of your post which is correct is the $/GB.

    Recent SSDs offer considerable more sequential performance in a single drive than even three Raptors on RAID-0. Plus on the more important random performance SSDs destory HDDs.

    As for the reliability part, Crucial and Intel SSDs are pretty much the standard bears for drive reliability, just stay away from the other vendors with the Sandforce controllers until they fix the BSOD and your fine.

    With the recent spat of many HDDs arriving DoA or failing within a short timeframe (see customer reviews on retailers such as Newegg) I have more trust on putting my critical data on an Intel or Crucial SSD drive vs. a HDD from a major vendor at the moment.
  • Abix - Tuesday, December 6, 2011 - link

    Successful troll is successful
  • EddyKilowatt - Tuesday, December 6, 2011 - link

    Hey, with views like these... shouldn't you be with your buds over on DailyTech making anti-EV sneers?

    (realize you were joking)

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