Along with Samsung's release of the 840 Pro SSD today, Samsung is also releasing a more mainstream oriented 840 SSD. It's based around the same Samsung MDX controller as the Pro series, but uses 3-bit-per-cell (TLC) NAND instead of 2-bit-per-cell (MLC) NAND found in the 840 Pro. The 840 Pro also has a firmware which is tuned for heavier workloads consisting of more writes and random IOs, whereas the 840 is designed more towards read centric (i.e. consumer) workloads.

Samsung SSD 840 Pro vs 840 vs 830
  Samsung SSD 830 (256,512GB) Samsung SSD 840 (500GB) Samsung SSD 840 Pro (256,512GB)
Controller Samsung MCX Samsung MDX Samsung MDX
NAND 27nm Toggle-Mode 1.1 MLC 21nm Toggle-Mode 2.0 TLC 21nm Toggle-Mode MLC
Sequential Read 520MB/s 540MB/s 540MB/s
Sequential Write 400MB/s 330MB/s 450MB/s
Random Read 80K IOPS 98K IOPS 100K IOPS
Random Write 36K IOPS 70K IOPS 78K IOPS

Samsung is actually the first manufacturer to publicly release a TLC NAND based SSD, so we will have very interesting time testing it. Remember, adding more bits per cell reduces endurance and also increases program, erase and read latencies. In a Q&A session Samsung couldn't tell us any exact P/E cycle numbers, but they claimed that the 840 has higher endurance than many competitors MLC based SSDs. We didn't get more specifics than that, but we hope to be able to test this as soon as possible. As for the performance, Samsung again wouldn't tell us any raw latency numbers, but they said their TLC NAND is roughly 50% slower than their MLC NAND. For a more in-depth look at the architectural differences between MLC and TLC, refer to our Understanding TLC NAND article.

Samsung SSD 840 Series Pricing
  64GB 128GB 256GB 512GB
Samsung SSD 840 N/A $109.99 (120GB) $199.99 (250GB) $449.99 (500GB)
Samsung SSD 840 Pro $99.99 $149.99 $269.99 $599.99

The regular 840 SSD will be available in capacities of 120GB, 250GB and 500GB. The increased amount of spare area makes sense given the use of lower endurance TLC NAND. The 840 will be available as a bare drive or in a notebook kit, which adds $20 to the prices in the table. Both, the 840 and 840 Pro will be available on October 15th.

Samsung only provided 256GB 840 Pro SSDs for reviews, so unfortunately we haven't been able to test the 840 yet. However, I should get our review sample later today and hopefully some other capacities of the 840 Pro as well. 

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  • Chas1 - Monday, September 24, 2012 - link

    Well, 255, I guess. Point being that's a lot of space that I don't think it has.
  • Nathan Leopold - Monday, September 24, 2012 - link

    How will this drive's controller handle different sized drives? Will the 512 have better performance? Will smaller drives have poorer performance?
  • haukionkannel - Monday, September 24, 2012 - link

    Hard to say at this moment, but 256 and 512 has same sized cache. 128 GB model has smaller cache, so at least there should be some difference.
    Interesting to see normal 840 model. It is slower in writing than 830 but in other aspect guite near or even better if specks are correct. But at this moment 830 offer better performance for the money.
  • Death666Angel - Monday, September 24, 2012 - link

    Thanks for the info and definitely looking forward to a review.
    Could you also post the MSRP at which the 830 launched? That would give a little hint towards street pricing (maybe). :-)
  • Zoomer - Monday, September 24, 2012 - link

    Please test latencies! We'll see how much of a difference there is, and perhaps for different drives as well.
  • Hacp - Wednesday, September 26, 2012 - link

    There might be a difference in latency, but the dram cash should mask all of it.
  • MamiyaOtaru - Wednesday, September 26, 2012 - link

    everything that drives down cost of Flash reduces write cycles. Smaller processes, now TLC. Sure controllers spread it around and are getting better, but there's a limit somewhere
  • Hacp - Wednesday, September 26, 2012 - link

    Yes, the individual chips will have less write cycles, but each chip can store more information. If you kept writing at 100mb/s on a drive till it dies, the drive with the larger capacity will generally last longer.
  • twotwotwo - Monday, October 1, 2012 - link

    If most of your writes go to just a little 'hot' data, there are sneaky ways to use a mix of expensive and cheap Flash to store it at minimum cost.

    For instance, if you're the human optimizing a database's storage system, you could put active tables on 'pro' drives and some rarely-written ones on 'consumer' drives. Or a single SSD could contain 3/4 MLC and a 1/4 SLC, and its controller could send all writes to SLC at first and evict the SLC's 'coolest', least-likely-to-be-rewritten pages to MLC as required.

    I don't think we'll see much of that soon, because complexity sucks and nobody is clamoring for a compromise between 'pro' and 'consumer'. But someday, it may take tricks like that to make ever-less-durable Flash useful at all.

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