The Samsung SSD 840

Now it's time to look at the Samsung SSD 840 itself. Performance differences between different capacities are tangible. Sequential write speed in particular increase with larger capacities. With MLC NAND based SSDs 256GB and 512GB models usually perform around the same because 256GB of NAND is able to saturate the limits of the controller but as TLC NAND has longer program times, you will need more NAND dies to hide the additional latency.

Samsung SSD 840 Specifications
Capacity 120GB 250GB 500GB
Sequential Read 530MB/s 540MB/s 540MB/s
Sequential Write 130MB/s 250MB/s 330MB/s
4KB Random Read 86K IOPS 96K IOPS 98K IOPS
4KB Random Write 32K IOPS 62K IOPS 70K IOPS
Cache (LPDDR2) 256MB 512MB 512MB

 

Samsung SSD 840 Pro vs 840 vs 830
  Samsung SSD 830 (256GB) Samsung SSD 840 (250GB) Samsung SSD 840 Pro (256GB)
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 250MB/s 520MB/s
Random Read 80K IOPS 96K IOPS 100K IOPS
Random Write 36K IOPS 62K IOPS 90K IOPS
Warranty 3 years 3 years 5 years

Performance wise the 840 does well but can't challenge the 840 Pro. Read performance is actually nearly on-par with the 840 Pro but write performance is behind due to the use of TLC NAND. I should add that write speeds are still adequate for a consumer drive. In some ways, the 840 can still be a healthy upgrade from the 830. Even though sequential write speed is lower, the increase in random read and write speeds can compensate. Still I suspect most 830 users will want to upgrade to the 840 Pro at least, if they choose not to wait for the next generation of SSDs.

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

Pricing isn't as aggressive as it could be but keep in mind that the above prices are suggested retail prices. Street prices can easily be ~$20 less and I wouldn't be surprised to see the 120GB SSD 840 retailing for less than $100 (and even $70-80 when on sale). Also note that we're still very early in the production of TLC NAND. Over time you can expect a more appreciable difference in pricing between TLC and MLC NAND.

Based on the chassis alone you can't really tell the difference between the 840 and 840 Pro. Both use a similar matte black plastic design. The 840 measures in at 7mm tall as well, just like the 840 Pro. It's only when you flip the drive around that you can see that it's actually an 840 and not 840 Pro.

Unfortunately, we don't have any pictures of the internals at the moment. Samsung uses special pentalobe screws (similar to MacBook Air) and finding suitable screw drivers in Finland isn't as easy as in the US. In order to get the review out as soon as possible, we decided not to wait for the screwdriver to arrive from the US. We are, however, looking at a PCB that's indentical to the 840 Pro (i.e. eight 32GB TLC NAND packages). The only difference are NAND part numbers.

The 840 Pro

Test System

CPU

Intel Core i5-2500K running at 3.3GHz (Turbo and EIST enabled)

Motherboard

AsRock Z68 Pro3

Chipset

Intel Z68

Chipset Drivers

Intel 9.1.1.1015 + Intel RST 10.2

Memory G.Skill RipjawsX DDR3-1600 2 x 4GB (9-9-9-24)
Video Card XFX AMD Radeon HD 6850 XXX
(800MHz core clock; 4.2GHz GDDR5 effective)
Video Drivers AMD Catalyst 10.1
Desktop Resolution 1920 x 1080
OS Windows 7 x64

 

Lower Endurance: Hardly an Issue Random & Sequential Read/Write Speed
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  • roedtogsvart - Monday, October 08, 2012 - link

    Might have to finally replace my Intel 320 with this. Very nice review Kristian Reply
  • Old_Fogie_Late_Bloomer - Monday, October 08, 2012 - link

    Both the Intel 320 and the Samsung 840 Pro support encryption...does the non-Pro 840 offer it or not? I'm swinging back towards getting an 840 Pro for my laptop because of the lack of encryption in consumer 830 drives.

    On a side note, I was disappointed to discover recently that my current desktop motherboard doesn't support hard drive passwords, which is a shame given the fact that my system disk (an Intel 320) does...oh well.
    Reply
  • ekon - Monday, October 08, 2012 - link

    The ATA password-based encryption these drives use is beset with issues, flaky motherboard support being just one.

    http://communities.intel.com/thread/20537

    On top of which, it's very poorly documented, and notice how reviews give it nothing more than a passing mention without testing the feature. A TrueCrypt/DiskCryptor alternative it is not :-/
    Reply
  • Samus - Tuesday, October 09, 2012 - link

    I've had my 320 for two years, no problems with encryption, ever.

    And I second roedtogsvart that I may FINALLY replace my aging SSD with one of these. I've been thinking Intel 520 for awhile but still don't trust Sandforce, even with Intel at the helm.

    Samsung and Crucial are keeping the controllers simple, which is why they have the most reliable drives outside of Intel's original X25-M/320 SSD's.
    Reply
  • Old_Fogie_Late_Bloomer - Tuesday, October 09, 2012 - link

    When you say "these drives", do you mean the Intel 320, the Samsung 840 Pro, or both? My T430 supports hard drive passwords for the expressly-stated purpose of allowing for encrypted SSDs, which is why I'm looking at the 840 Pro in particular.

    It seems like the only downsides would be having to enter the password to use the computer, and having to use a motherboard that supports HD passwords to access the drive (so I couldn't just plug it into my current desktop if something were to happen to my laptop and it were off for repair or whatever).
    Reply
  • ruberbacchus - Saturday, October 20, 2012 - link

    On one hand, it seems to me that the potential gains performance-wise with hardware-based rather than software-based encryption are enormous; particularly so on older computers with slower processors. On the other hand, an encryption solution that is not properly documented as well as thoroughly verified and verifiable does simply not exist as a solution; confidence in the implementation is essential to the deployment of encryption. Unfortunately, it seems impossible to obtain clear references to how encryption works in this new class of SSD's. I read somewhere that it should conform to the OPAL standard, which mandates hardware-embedded keys. I am not sure this is such a great idea, for two reasons:
    - the keys will potentially be known to the manufacturer;
    - the keys will be open to physical attacks on the chip controller.
    With TrueCrypt e.g., the user himself generates the encryption keys, the master key used for encrypting the data as well as the header key used to wrap the master key. The latter is tied to the user's password. With hardware-based encryption, passwords may be used for authentication, but the keys will not necessarily be derived from the password. Unchangeable encryption keys weakens the security. In order for the system to be trustworthy, the user should be able to generate and re-generate at will their own encryption keys. At the moment it is not clear this is the case.
    Reply
  • A5 - Monday, October 08, 2012 - link

    I guess I'm old fashioned and don't throw away my laptop every 6 months, but a 3.5 year lifetime seems really really short. Reply
  • crimson117 - Monday, October 08, 2012 - link

    Agreed; maybe for a video card, but I expect longer than 3.5 years out of my hard drives. Reply
  • repoman27 - Monday, October 08, 2012 - link

    Really? I rarely expect a consumer grade HDD to last much longer than that these days. In fact, I've seen an alarming trend of drives failing just past the 2 year mark, and still within the 3 year warranty period. (RMA'd one last week even.) Reply
  • travbrad - Wednesday, October 10, 2012 - link

    I had a 80GB WD that lasted 8 years without failing. I eventually had to stop using it simply because it was too slow. I also had a 250GB WD drive that I used for 5 years (then switched to all SATA). Now I have a 640GB drive that I've been using for almost 4 years. My brother has a couple 500GB drives in his system that have been running for 4-5 years as well.

    Maybe I've just been really lucky, but the only drive I've personally had fail in the last decade was a Hitachi drive (obviously selected for cost not quality) in my HP laptop.

    Now at work it's a different story. Those pre-built machines cut every corner they can to bring costs down so they end up with low quality components (especially PSUs). Even in that situation there is a fairly low number of hard drive failures though (considering how old most of the machines are)
    Reply

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