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List of SSDs that support ATA TRIM

ThraxThrax Professional Shill, Pokémaster, Watch SlutAustin, TX Icrontian
edited Jul 2012 in Hardware
<h3>What is ATA TRIM?</h3>
An SSD's total size is composed of thousands of smaller units called "blocks," which average about 512k these days. SSDs deliberately try to spread written data across all of these blocks so as not to prematurely wear out the memory chips, which can only accept a limited number of writes. This technique is called wear leveling. Over time, wear leveling guarantees that every block on the SSD will receive a write of data at one time or another.

When this is combined with Windows' delete mechanism, which only marks space as free rather than physically removing the data, an SSD is guaranteed to get gummed up with a hodgepodge of deleted and undeleted files. When the SSD's physical cells are full, regardless of the displayed free capacity, the drive must perform a complicated routine called the read/erase/modify/write cycle to store new data.

An REMW cycle forces an SSD to scan its blocks for deleted but unpurged files, copy active data to cache, purge the deleted files, append the new data to the data in cache, and then write the cache back to the new free space. This is called write amplification, and in serious cases, it can force an SSD to shuffle up to 20GB of data just to write 1GB of new information. This causes significant performance issues for SSDs.

The solution to this problem is to let SSDs physically erase files the moment they are deleted in the OS, and that is precisely what the TRIM command does. Windows 7 and Windows Server 2008 R2 are the only Microsoft OSes that support it, and the feature cannot be used without support from both the drive's controller and firmware.

Comments

  • MAGICMAGIC Furniture City, Michigan Icrontian
    edited Oct 2009
    What sort of life expetancy can you expect from a SSD drive using ATA-TRIM over a drive that doesnt utalize it, if there is a difference? Although this may be a false stigma, the fact that these drives can "wear out" is the biggest deterrant for me(and probabley others)from purchasing one with the prices being as high as they are for the latest featured drives.

    If these companies offered and incentive such as a rebate on another after the drive has reached its life expectancy would be nice.
  • ThraxThrax Professional Shill, Pokémaster, Watch Slut Austin, TX Icrontian
    edited Oct 2009
    ATA TRIM isn't a longevity thing, it's a performance thing. When windows deletes a file, it simply marks that space available for overwriting--the files aren't actually purged. That's fine for mechanical disks, because they don't get any slower when that happens. It's bad for SSDs though, because write performance is directly tied the fullness of a NAND cell.

    If NAND cells the drive wants to write to are full with 10% legit files and 90% bullshit (unpurged deleted files), it has to copy all of the legit user data to cache, erase the cells to clear the 90% useless data, modify the cache's data with what YOU want to write, then copy it all back. This is called write amplification, because the amount of data being moved around is an amplified amount, relative to the data you're actually looking to write.

    The ATA TRIM command deletes the file from the NAND cells the minute they're deleted in the OS, so the cells only ever contain active user data. The only time it would have to perform this read/erase/modify/write action is if the cells it wants to write to are 100% full with real user data.

    Obviously this extra file juggling does have some longevity considerations, but they're minimal. The real benefit of TRIM is an SSD that does not sharply degrade in performance over time through simple usage.

    As for your longevity questions, i.e. "How long do I have before this drive is dead?" That is exactly what I am looking to answer and, possibly, clear the air about. I don't have a clear answer for that yet, because every drive controller has a different write amplification factor that can be as big as 40:1, or as little as 1.1:1. If my research pans out, I will be able to say "These SSDs are good for XXXGB of data per day for XXX years." That is my goal.
  • PreacherPreacher Potomac, MD Icrontian
    edited Nov 2009
    Thrax,
    Very interested in an article and recommendations. I have the OCZ Vertex and as I am about to put Win 7 on three computers over Turkey Day. I'd like to make sure I install the OS correctly on the SSD with TRIM firmware and Win 7.
  • ThraxThrax Professional Shill, Pokémaster, Watch Slut Austin, TX Icrontian
    edited Nov 2009
    Short version: Use the SSD as the boot drive. Move the swap file to a mechanical disk, disable 8.3 file name support, disable the SuperFetch and Windows Search services. Do not use the SSD for mass storage, use it to store your most intensive programs and large data sets so that they load quickly.

    Do not full format the disk. Quick format only.
  • GooDGooD Quebec (CAN) Member
    edited Nov 2009
    Loved the way you did summerize everything in this short version, its the best "all-in-one" short post i've read about how-to-use-a-SSD :)

    Can't wait to read your article ! :D
  • PreacherPreacher Potomac, MD Icrontian
    edited Nov 2009
    Thrax wrote:
    Short version: Use the SSD as the boot drive. Move the swap file to a mechanical disk, disable 8.3 file name support, disable the SuperFetch and Windows Search services. Do not use the SSD for mass storage, use it to store your most intensive programs and large data sets so that they load quickly.

    Do not full format the disk. Quick format only.

    Still eagerly awaiting the article, but thanks for the executive summary. I already had setup the SSD as my boot drive and apps only as well as disabling the Window Search. However, I had forgotten to move the swap file, to disable Superfetch, and 8.3 filenames. Many thanks.
  • pragtasticpragtastic Alexandria, VA Icrontian
    edited Nov 2009
    Out of curiosity, what's the problem with having your swap on the SSD? Too many unnecessary writes?
  • SnarkasmSnarkasm 's-Hertogenbosch, The Netherlands Icrontian
    edited Nov 2009
    Yep. I'm curious about superfetch, though.
  • pragtasticpragtastic Alexandria, VA Icrontian
    edited Nov 2009
    I believe I have my swap pointed to my SSD at work right now... gonna have to fix that.
  • ThraxThrax Professional Shill, Pokémaster, Watch Slut Austin, TX Icrontian
    edited Nov 2009
    All of them make unnecessary writes to disk, and superfetch is merely a crutch to overcome the relatively low burst of mechanical disks.
  • RyderRyder Kalamazoo, Mi Icrontian
    edited Nov 2009
    Disable any fetching (pre, super, etc), Drive indexing, auto/scheduled Defrag (for sure). Those are the only "tweaks" I use in 7.

    I have a swap file on my 7 installs, I have not gone to tweaking that yet.
  • pragtasticpragtastic Alexandria, VA Icrontian
    edited Nov 2009
    I went ahead and moved my swap file over to the mechanical disk on my workstation today.
  • GooDGooD Quebec (CAN) Member
    edited Nov 2009
    stupid question maybe, but how can we tell to windows that we want it to swap file over to another drive ?

    Is it in Performance options / advanced tab / virtual memory ?

    I can disable the swapping on C: and enable it on my D: , is it how we can do it ?

    Just curious since i will buy and SSD drive sooner than later :)
  • ThraxThrax Professional Shill, Pokémaster, Watch Slut Austin, TX Icrontian
    edited Nov 2009
    That's how you do it. :)
  • pragtasticpragtastic Alexandria, VA Icrontian
    edited Nov 2009
    Exactly the process I used today GooD :)
  • edited Nov 2009
    Hope you research the pagefile's effect on longevity as well. I suspect that pagefile writes to an SSD don't add up to a lot of harm. If you choose to move the pagefile to a hard disk, you trade some performance for that unknown gain in longevity. And you probably got the SSD for performance in the first place...
  • ThraxThrax Professional Shill, Pokémaster, Watch Slut Austin, TX Icrontian
    edited Nov 2009
    I'm willing to make the assumption that anyone who runs a performance SSD has at least 4GB of RAM, thereby minimizing page file usage. As a result, moving the page file to a mechanical disk would have a minimal performance impact outweighed by the addition of an SSD and the benefit of improved SSD lifetime.

    As a hard and fast rule, any writes to an SSD not made by the user are a bad idea.
  • edited Nov 2009
    Thrax wrote:
    As a hard and fast rule, any writes to an SSD not made by the user are a bad idea.

    Looking forward to seeing how costly SSD writes are in practice.
  • ardichokeardichoke Buttes Master B Lansing, MI Icrontian
    edited Nov 2009
    Heh... Having 4GB of RAM doesn't seem to cut down on page file usage for me. I just rebooted my desktop last night, my page file is currently sitting at 2.5GB, at least according to the orbmu2k memory monitor widget. This despite the fact that only 2GB of memory are in use.
  • pragtasticpragtastic Alexandria, VA Icrontian
    edited Dec 2009
    So if you're running an SSD these days and NOT on Win7 or Server2008, I suppose clean formats of the disk are the only way to clean up the mess of leftover deleted files?
  • RyderRyder Kalamazoo, Mi Icrontian
    edited Dec 2009
    Formatting does not clean the Nand.

    If you are not using an OS that supports TRIM, you want an SSD running a FW that has "Garbage Collection" (OCZ's term for it) or whatever the manufacturer puts in place to keep free blocks available.
  • ThraxThrax Professional Shill, Pokémaster, Watch Slut Austin, TX Icrontian
    edited Dec 2009
    This thread has received a major, major overhaul.
  • PreacherPreacher Potomac, MD Icrontian
    edited Dec 2009
    Thrax wrote:
    This thread has received a major, major overhaul.
    And a major re-reading, in my case. Thanks, Thrax.
  • ThraxThrax Professional Shill, Pokémaster, Watch Slut Austin, TX Icrontian
    edited Feb 2010
    <h3>Version 3.0:</h3>
    Version 3.0 of the SSD list is here! This is the second largest update this document has received since it was expanded to include the current information sets.

    As you can see below, several new SSD series have made the list, including a first-time showing by Mushkin, which has finally published TRIM data.

    Finally, I'm still on the lookout for the information requested in the "wanted" section. If anyone has any particular insight on these topics, a PM would be greatly appreciated.

    Cheers!

    ADDED:
    • Kingston SSDNow V series
    • Kingston SSDNow V+ series
    • Corsair Reactor series
    • Corsair Nova series
    • OCZ Vertex LE series
    • Mushkin Io series
    • New OCZ firmware versions

    REMOVED:
    • A-DATA S596 series

    WANTED:
    • NAND cell vendor(s) for Corsair Nova series
    • NAND cell vendor(s) for Corsair Reactor series
    • TRIM status for Runcore SSDs
    • Availability for A-DATA S596 series
  • ThraxThrax Professional Shill, Pokémaster, Watch Slut Austin, TX Icrontian
    edited Feb 2010
    <h3>Version 3.1:</h3>
    ADDED:
    • SanDisk G3 series

    WANTED:
    • NAND vendor(s) for SanDisk G3 series
    • Controller model number for SanDisk G3 series
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