back to article Creaky PC? SanDisk gives users a NAND with speedy '3-bitter' SSD

SanDisk has pushed out an Ultra II SSD for retrofitting to PCs that uses lower cost 3-bits-per-cell NAND technology. TLC or 3 bits per cell flash stores 50 per cent more information in each cell than MLC (2 bits per cell) and is cheaper to make on a cost/bit basis. But the number of times TLC flash can be rewritten, the P/E …

  1. Steve Davies 3 Silver badge

    El-Reg? are Units a problem?

    Quote

    The original device did sequential reads up to 280GB/sec and sequential writes up to 270GB/sec. Ultra II blows these numbers away with reads up to 550MB/sec and writes to 500MB/sec. Random performance is up to 99,000 read IOPS and 83,000 write IOPS.

    Spot the error there?

    What is the difference between the Sandisk drives and the Crucial M550's? To me that is more important that comparing these to the AMD/Radeon re-badged ones.

  2. jason 7

    Differences?

    Comparing SSDs is getting like ram comparisons. My heart sinks when I see another DDR3 ram group test on the net.

    Give it another 18 months and they will all be within +/-2% of each other.

    Bottom line, unless you have a very very specific need...they all work fine.

    1. Neil Barnes Silver badge

      Re: Differences?

      My need is for an SSD that costs the same as a similar sized spinning rust device... I considered one last month when I replaced a disk in my laptop but fifty quid for a gig of hard drive made it a no-brainer.

      1. Tom_

        Re: Differences?

        You should have been able to get about 1,000 times that for fifty quid, mate.

        1. Neil Barnes Silver badge

          Re: Differences?

          ach, too early in the morning. I did. :)

    2. Paul Shirley

      Re: Differences?

      There's still some fast shrinking value comparing the IOPs but yes, they're all coming up against SATA6 performance limits. However those comparisons are what tell me I can have power loss protection for little or no premium or performance tradeoff.

      So still useful even if the typical review focusses to much on irrelevant speed comparisons instead of features. There'll be a time when all SSDs have similar feature sets but we're not there yet.

      1. jason 7

        Re: Differences?

        That's it really. SSD reviews should be 90% about value add and "what makes this SSD special' and just 10% on performance.

        1. SineWave242

          Re: Differences?

          "That's it really. SSD reviews should be 90% about value add and "what makes this SSD special' and just 10% on performance."

          + I would absolutely add durability/reliability figures to that.

    3. joed

      Re: Differences?

      The law of diminishing returns is in full effect when considering RAM upgrades yet one can still get modules that run at higher frequency (the clear differentiation), run at higher frequency without increasing the voltage (this does matter for some mobos, also trivial power savings) or run at higher frequency without increasing timings (often more important than higher frequency). Picking the best RAM (and later finding the best config on the actual system) is hence pain usually not justified by gains (but if you have to prove you're "the best" you do this regardless).

      Now, when it comes to SSDs I'd avoid calling 3-bit tech Ultra - it may be cheaper but I'd rather spend my money elsewhere.

  3. frank ly

    Percentages and bits

    "TLC or 3 bits per cell flash stores 50 per cent more information in each cell than MLC (2 bits per cell) "

    Three bits gives you eight possible values; two bits gives you four possible values. That sounds like one hundred percent more information.

    1. JeffyPoooh
      Pint

      Re: Percentages and bits

      "Three bits gives you eight possible values; two bits gives you four possible values. That sounds like one hundred percent more information."

      By your logic, a 6 TB HDD can hold more information than would fit into the known Universe.

      1. This post has been deleted by its author

      2. frank ly

        Re: Percentages and bits

        I'll try again:

        I'm not talking about bytes used to represent characters, etc. I'm talking about the number of possible states that can be represented by a small number of bits.

        A 6TB HDD could in theory have 2^(48*10^12) possible information states, but most of these would be highly unlikely since they'd have no use or meaning in the context of its normal use. When you're dealing with a small number of bits, then all possible states are equally likely.

    2. lpcollier

      Re: Percentages and bits

      Yes and no. Each additional bit doubles the precision of what can be stored, but you can't store two independent 2-bit numbers in 3 bits. Think about the old 8-bit/16-bit divide. You can store two 8-bit numbers in a 16-bit word, or store a 16-bit word as two 8-bit bytes (LSB and MSB). You can't store 8x 8-bit bytes in a 16-bit memory location.

  4. dogged

    M.2

    Interested in this format instead, please.

    That way I can build a mini-ITX rig that has no "drives" at all.

    1. Stuart Halliday

      Re: M.2

      Why not look at the 400GB SSD RAM sticks?

      1. dogged

        Re: M.2

        That's interesting. Where might I find such a beast?

        EDIT - wait. Not interested. You only get two DIMM slots in a standard mini-ITX motherboard.

  5. Anonymous Coward
    Anonymous Coward

    An old fart adds...

    At this rate, today's kids are going to think of spinning platters and skimming heads as being every bit as quaint and mechanically Rube Goldberg as today's generation think of punch cards or CD burners.

    1. Anonymous Coward
      Anonymous Coward

      Re: An old fart adds...

      How old is the generation that don't think punch cards are quaint?

  6. channel extended

    Other uses.

    The best thing about punch cards is that you can use them to cook your weiner.

    (oops: I meant your hot dogs on the camp fire! NB Yes I did use punch cards OnceUponaTime.)

  7. Fungus Bob
    Boffin

    Endurance

    From an Anandtech article about the Samsung 840 TLC SSD:

    http://www.anandtech.com/show/6337/samsung-ssd-840-250gb-review

    "With perfect wear-leveling and write amplification of 1x, you would get 256,000GiB (that's ~275TB) of writes out of a 250GB Samsung 840 with TLC NAND and 1,000 P/E cycles. That is still a lot but wear-leveling and write amplification are never perfect. Giving any specific numbers for endurance is hard because every drive behaves differently and users have different workloads, but it's unlikely for a light consumer workload to see more than 10GiB of writes per day. That's 3,650GiB per year, which is only 1.4% out of 256,000GiB. In the real world NAND writes will be bigger than host writes but even with a write amplification factor of 10x, you will only end up writing 36,500GiB each year and exhausting ~143 P/E cycles out of the available 1,000. In other words, it would take roughly seven years for you to wear out the NAND."

  8. agricola
    Boffin

    People won't learn.

    So Sandisk refuses to learn ANYthing from Samsung's TLC fiasco.

    Fiasco: Samsung's falling, falling, falling prices on their TLC devices as potential customers stay away in droves, regardless of all of Samsung's hype.

    Sandisk, people are a lot smarter than either you or Samsung give them credit for.

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