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The Longevity Of Three-Bit-Per-Cell NAND

Tom's Hardware's AMA With Samsung, In Its Entirety
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Q. Does Samsung intend to branch out into peripherals in addition to their storage products? Also, with regards to system memory...what are your thoughts on DDR4 vs. HMC? Obviously you probably can't give details, however, are both types of memory being investigated by Samsung?

A. The area where my division focuses on is OEM SSD offerings where our customers take our SSDs and put them into their product offerings which are then sold to end-users. Our division is more focused on enabling our customers to add value on top of our SSD. With that being said, we have not had any announcements around peripherals using SSDs for our division. Regarding HMC & DDR, my expertise is more focused on SSDs and not on the RAM side. If you are interested in me forwarding to our retail division, please send me your question to: ssd@ssi.samsung.com and I will forward your question to the retail team.

Q. I’ve seen several tests done by review sites that mention that there is no fear of longevity issues when it comes to TLC NAND with Samsung’s great controller/flash technologies and the 840 EVO looks like a great drive that I want to order. What your personal experience is with this newer nand tech and if we will be seeing the 840 EVO in early August?

A. Samsung was first to successfully deploy 3-bit MLC technology into SSDs. There are three main characteristics that go into determining the "longevity" of a SSD: The type of NAND used, the write workload type and amount, and the capacity of the drive. So, as you see, the type of NAND (e.g., 2-bit MLC, 3-bit MLC) is only one piece of the puzzle when determining what the longevity will be.

3-bit MLC has not always been an option for SSDs but the timing is right to make the switch. Two things have made this possible: the capacity points of SSDs have increased to levels that make the longevity a non-issue and the controller/DSP technology that reads/writes to the NAND Flash has improved each year. For example, if you have a given amount of writes you can do to the NAND Flash itself, and you go from 64GB to 128GB, you double the amount of overall writes (GB's) you can do over the life of the drive. When you go from 128GB to 256GB, you double it again. If we were still using 64GB drives today, 3-bit MLC would likely not be an optimal solution for a 40GB/day workload. However, because we have moved to higher capacities, we have doubled and quadrupled the amount of writes possible to the SSD that weren't possible at smaller capacity points.

We have done tests using typical PC workloads (PCMark) to simulate 40GB's of writes per day on a 256GB 3-bit MLC SSD and have shown it to reach the specified limits of the NAND in 13.5 years; This is a long time in the life of technology. Hard drives were roughly 20GB thirteen years ago. Furthermore, some reviewers have shown that the 3-bit SSDs they have tested can handle much more writes than this. If you move to 2-bit MLC, you can bump this up to over 47 years. The question is: do you really need more than 13 years of writing 40GB's per day? If the answer is yes, then perhaps 2-bit MLC is for you. But, in reality, most people do not write 40GB's every day to their drive and do that for 13 years. And, it is likely the user would have already replaced their entire computer within that 13 years.

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  • 4 Hide
    LonelyMan , August 2, 2013 9:58 PM
    I hope that in 4 to 5 years when I'll build a new desktop, I can buy a high-end sata ssd of 1tb for 300 or less. And I hope that Amd will offer competition to Intel when it comes to processors. And that Titan will be out hopefully.
  • -2 Hide
    smeezekitty , August 2, 2013 9:59 PM
    I don't care for how they refer to 3 bit per cell as MLC where TLC is generally reserved for that.
  • 1 Hide
    Someone Somewhere , August 2, 2013 11:43 PM
    Technically, 3 bpc is just as multi-level as 2bpc. Strictly speaking, SLC probably should be called MLC - there are two different charge levels for each cell. You can't store any data without multiple options.

    Some of their answers were somewhat evasive though...
  • 1 Hide
    smeezekitty , August 2, 2013 11:46 PM
    Honestly MLC (2 bit) should be DLC

    But it is still best not to break the currently accepted terminology.
  • 3 Hide
    Someone Somewhere , August 2, 2013 11:49 PM
    Actually, I'd argue that the whole 'level' thing is misleading. A TLC has 8 different voltage/charge levels.

    I'd support calling it 1bpc/SBC (or similar), 2bpc/DBC, etc. But keeping continuity is a good idea.
  • 0 Hide
    zodiacfml , August 3, 2013 12:01 AM
    at least, the guy explained the values of less enduring ssds but with capacity gains. he also reminded that desktop users rarely need more write endurance. a harddisk dies faster than a weak endurance ssd.
    i haven't experience an ssd yet due to various mobile options keeping me busy nowadays but I would definitely get an ssd soon.
  • 0 Hide
    Movieman420 , August 3, 2013 4:31 AM
    Absolutely no info regarding aftermarket pci-e drives. Ok, so they are shipping such solutions with oem pcs...95% of enthusiasts wouldn't touch a pre-built PC with a 10ft pole. They keep talking about their pci-e drive for lappys and again, it's an oem thing...don't get me wrong, their new pci-e drive looks great but as a desktop enthusiast, it's not a reality. Will Samsung be launching a pci-e line of drives for after market use? If they will be sticking to the m.2 form factor, will there be pci-e adapters for our PCs? Also, will there be an EVO 'Pro" ssd launched? These are questions I would have asked if I could have been there.
  • 0 Hide
    sire_angelus , August 3, 2013 2:41 PM
    What's the point of having an AMA if half the answers are out of topic with the questions?
  • 1 Hide
    lp231 , August 3, 2013 3:40 PM
    Hmm. I don't remember seeing this AMA on Tom's front page.
    Ah well...
  • 0 Hide
    m32 , August 4, 2013 1:12 AM
    lp231, I'm just like you. I didn't see it at all. I love Samsung ;) ! I kinda wish it was more than RAM and SSD talk, but I enjoyed reading this article. Thanks to Toms and the sponsors that participate in these "AMAs".
  • 1 Hide
    ssdpro , August 4, 2013 4:11 AM
    This is not what I expected. Some of those answers are barely connected to the question. This basically sums up Samsung. Top tier products but the consumer/customer relationship is non-existent. Based on my own experience with a half dozen Samsung SSDs, a dozen OCZ SSDs, and a half dozen Intel SSDs I wouldn't say any one of those are more or less reliable than the others. Samsung does have the weakest support by far so it is fitting that the apple doesn't fall far from the PR tree.
  • 0 Hide
    lp231 , August 5, 2013 8:35 AM
    Quote:
    lp231, I'm just like you. I didn't see it at all. I love Samsung ;) ! I kinda wish it was more than RAM and SSD talk, but I enjoyed reading this article. Thanks to Toms and the sponsors that participate in these "AMAs".


    Yep, Samsung doesn't just make ram and SSD, they make other products too. It would also be nice to know what else they do.
  • 0 Hide
    g00fysmiley , August 5, 2013 9:44 AM
    seems like it was all storage subject, would have loved to hear a more variety of topics from a company like samsung otherwise it should have been "ama about our ssd's"
  • 0 Hide
    ammaross , August 6, 2013 7:42 AM
    Shame the SSD marketeer was dodging and dismissing the HDD questions. Spinpoint drives were my personal favorite. Just because someone can get a 250GB SSD, doesn't mean they don't want an HDD to go along with it. I've got 4 Spinpoint drives, 2 Western Digital Green drives, and 2 Seagate drives (all +/- 2TB) in my computer ATM (mainly because my other WD and Seagate drives died, but not my Samsung ones). Yes, we understand he's super-excited and thinks the world should be flash, but spinning rust has its place too.