TRIM & encypyion

Discussion in 'MacBook Air' started by Tech198, Sep 9, 2013.

  1. Tech198, Sep 9, 2013
    Last edited: Sep 10, 2013

    Tech198 macrumors G5

    Mar 21, 2011
    Australia, Perth
    Hi all.

    Is is a good idea to use FileVault 2 on an SSD ?

    Since TRIM is use to tell the drive to wipe out blocks "not in use", basically the opposite of how hard drives still store deleted data in sectors, they just wipe out the contents to make it invisible to the OS), and the fact that FV encrypts on the drive anyway of SSD's, will using FV slow down performance?

    Plus, the fact you can use Disk repair or maintenance utilities like SpinRite, on a SSD, "the term going round is it will severely affect the life of the drive", how come its ok to securely zero out data, or securely empty the trash, on them then ?

    OK, you may be securely wiping only 1 file over the course of say x month, which may not be too bad, but still, this would still effect the drives loge, would it not? Where do you draw the line?

    Since HD's has nothing to worry about.
  2. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    There is no problem using FV2 on a SSD. There is a slight performance hit due to encryption, but it is small. Here are some tests with and without FV2 on.

    I use it on my Macbook Air and do not notice any slow down at all.

    Don't worry about wearing out your SSD. It is true that each NAND cell has a finite number of write cycles, but that said, you will be on a new computer long before the SSD wears out. Good article here on the topic.
  3. Boyd01 macrumors 68040


    Feb 21, 2012
    New Jersey Pine Barrens
    Thanks for the link, I have been wondering about this myself. I guess it depends on what you use your computer for. Quoting from the article, "Overall the hit on pure I/O performance is in the 20 - 30% range."

    I would love to use encryption, but I also use Final Cut Pro and Logic Pro. I suspect that a 20-30% i/o performance hit would be noticeable there.
  4. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    I am admittedly not doing anything that would tax may machine, so you may notice a hit. It is easy to just try it out then turn it back off it it ends up being more of a hit than you can live with.
  5. w00d macrumors member

    Sep 14, 2010
    I can't remember what my speeds were before setting up FileVault2 but I don't think it was 20% faster. Could be wrong of course!

    2013 MBA 13" i7 / 8GB / 256 / FV2 enabled

    Attached Files:

  6. scaredpoet macrumors 604


    Apr 6, 2007
    Absolutely. If you have any data of value on your laptop, you should encrypt it. If you laptop were to get stolen, at least the data would be reasonably protected against being used for identify theft.

    And no, using encryption will not harm your SSD.

    The use of FV2 should have no effect on the implementation of TRIM.

    I wouldn't say that zeroing it out is not okay at all, unless you're disposing of the drive completely and want to be sure the data on it is really gone. Securely zeroing out the drive will add to its wear. And likely so while "tools" like SpinRite (which IMO, had dubious usefulness even for traditional hard drives).

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