Performance vs. Transfer Size

ATTO is a useful tool for quickly measuring the impact of transfer size on performance. Similarly to the 840 Pro, the 840 is a high performer at small transfer sizes, which is an area I think too many SSD vendors are ignoring. Not all IOs are huge in size and while the small IO read/write speeds aren't big enough to be used for marketing, they play a role in real world performance. In write speed the 840 tops out at 250MB/s, which is low compared to many other SSDs but otherwise the 840 performs very well.

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AS-SSD Incompressible Sequential Performance AnandTech Storage Bench 2011


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  • JellyRoll - Saturday, November 24, 2012 - link

    Digital Signal Processing has nothing to do with the voltage states of the NAND. It is processing of the actual signal that comes from the NAND packages.
    DSP is used for multiple technologies, from audio to video to radar. These devices do not utilize nand, and DSP has zero interaction with the NAND itself, it merely reduces and corrects the amount of errors that come from the NAND.
    here is a primer on DSP:
    There needs to be more research before these incorrect explanations are posted.
    "Even though DSP doesn't make NAND immortal, it causes a lot less stress on the NAND, allowing it to last for more P/E cycles than what you would get without DSP."--This statement is entirely untrue, as DSP has no interaction with the NAND itself. It seems there is a bit of guesswork going on when writing this article.
    DSP simply corrects errors. With lower endurance NAND you experience more errors.
  • PanzerIV88 - Thursday, December 27, 2012 - link

    I just bought on Boxing Day that Samsung 840 250Gb for 150$ + Taxes. The sequential write speed is what scares the most but other than marketing bs it's actualy what's the less important. There's much more happening into the small files or reading speed which it shines in. I'll definitely replace my Vertex 4 128Gb which isn't as amazing as I thought it was, mostly since I learned that once it reaches 50% capacity, it turns into storage mode instead of performance and the write speed falls of 2 to 3x!!! I can confirm this with benchs I've done, it's really sad..

    Also thought of doing a Vertex 4 Raid 0 but other than bragging with bench numbers, seriously wtf does 600-800Mb/s is gonna do for a daily light load or gaming?! Totaly nothing more... so I'll save my money.
  • sriggins - Saturday, March 16, 2013 - link

    I have been using an 830 in my MacBook Pro since last October. I use FileVault 2 and do a ton of compiling on the drive. Performance has been steady. How does using OS X encryption affect the life of the drive? Is there any way to tell how many writes have been done so far? Reply
  • brainfuck - Wednesday, July 03, 2013 - link

    Is there any way to find the Erase Block Size of Samsung 840 250GB?
    so that i can align my disk accordingly

  • WildBillvms - Wednesday, May 21, 2014 - link

    Great Drive , but if you have memory problems click here ----> Reply

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