Different question about TRIM

Discussion in 'MacBook Pro' started by borisiii, Apr 26, 2013.

  1. borisiii macrumors 6502

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    #1
    I got a deal on an OCZ Agility 3 SSD just over a year ago, and I put it in my 2010 13" MBP. At first it was really fast, with <15 second boot times and one bounce app opening.

    Over about 6 months it slowed right down, to the point where it wasn't noticeably faster than a normal hard drive. I reinstalled the OS, and this brought most of the speed back, but the effect only lasts a couple of months and I need to keep reinstalling.

    So... I've arrived at the conclusion that I should enable TRIM, but here is my question: if I use a TRIM enabler, will I start seeing speed improvements just like that? Or should I reinstall the OS, or take any other measures first (like zeroing out the drive), before enabling TRIM to maximise the benefit? Thanks.
     
  2. WAM2 macrumors 6502a

    WAM2

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    #2
    Do not zero the drive, it can harm the SSD.

    Reinstall the OS, and before installing anything, update to 10.8.3 (if on ML), then run trim enabler. Then your good to go.
     
  3. borisiii thread starter macrumors 6502

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    #3
    Oh really? I read in this anandtech guide that it was the best way to restore performance.

    http://www.anandtech.com/show/2738/11
     
  4. WAM2 macrumors 6502a

    WAM2

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    #4
    Yes, but Zeroing out the drive fills the disk space with zeros and clear it. This can actually harm an SSD, as its the secure erase method for Hard Drives. SSD's have a secure erase command that electrically "zaps" the data in the flash memory, making it impossible to recover. There are several programs you can download to do this, but when I secure erase my SSD's i use Parted Magic, then go into the "Erase Disk" application (not the partition application). Just burn Parted Magic to a disk and boot from it using default settings.
     
  5. wonderspark macrumors 68030

    wonderspark

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    #5
    How close to full is the boot SSD? They say you need 10% minimum, and 20% is as little space as I'd ever leave.
     
  6. Mr MM macrumors 65816

    Mr MM

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    #6
    it doesnt really matter, nand longevity is one thing that we dont need to worry about.

    If you are pro cinema editor you will know when to change your scratch disk, which depends on the workload is around 6-12 months

    So average user concerned about longevity? bollocks they are rated much more than that, check storage review
     
  7. borisiii thread starter macrumors 6502

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    #7
    Thanks for this. I've had a look and it seems OCZ have their own dedicated utility for wiping wiping the drive so I'll use that to do it when time permits. I have ML so I'll do a clean install, enable trim, then see where I get to.

    It's about 50% full so I don't think that's the issue - it just seems this particular model has really bad garbage collection. It's a secondary computer, and I mainly use it for safari and mail, so it's not like it's getting millions of read/write cycles either.
     
  8. shootist macrumors regular

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    #8
  9. negativzero macrumors 6502

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    #9
    Sandforce based SSDs have their own garbage cleaning routine written into the hardware, which negates the need for Trim Enabler. Anyway, Trim and garbage collection helps optimise WRITE operations, not READ. So there is something else at play here which is slowing down the performance of the OPs drive.
     
  10. dusk007 macrumors 68040

    dusk007

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    #10
    Zeroing out empty space does not hurt the SSD.
    It is just writing data and nothing fancy about it.

    The point being that simply enabling Trim doesn't do anything by itself. So you need to fill up all the (to you the OS) empty space with something (zeros or ones doesn't matter just something) and delete it with Trim enabled. So the SSD now knows what all the empty space is.
    There is no harm in doing that and it is all that should be needed to restore most of your performance in time. If read performance is bad though that means your data is to fragmented most likely and that will take a little time to resolve itself. I had the same issue with my Vertex 2. Just use zero out empty space commands if available or copy paste a big file until you have no space left. Next delete all the nonsense data you just created. Write performance picks up immediately. Read performance of old data may require a bit of GC consolidation which is now easy with enough free space.

    My Vertex 2 really suffered badly (one third performance) from not having Trim enabled. Kept its performance later. Sandforce GC is BS without Trim. It just isn't aggressive enough or lacks enough spare area.
     
  11. Weaselboy Moderator

    Weaselboy

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    #11
    It kind of does, but very very minimally. The OPs SSD uses MLC NAND chips that are rated for 3,000 write cycles. So if you do a Disk Utility secure erase, that writes to every bit of free space on the drive, thereby reducing remaining write cycles by one. Not a big deal, but also unnecessary.

    OP>> If you want to restore performance (assuming here it is reduced due to no TRIM), just enable the trim hack then do a command-s boot to single user mode. Now type in the command "fsck -fy" (without the quotes) and hit enter. This will TRIM all free space on the SSD and accomplish your goal.

    I would be curious to see a before and after speed test with this?
     
  12. dusk007 macrumors 68040

    dusk007

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    #12
    1 cycle of 3000?
    If you did that every day, you would still have 8 years of life from that drive plus the time the nand outlives its supposed death (as those estimates are usually really conservative).

    I would consider that less than minimal. Also empty space might only be 30% of the actual nand. So it is more like 1/3 cycle.

    Just by normal use. Downloading. Surfing doing mostly boring stuff I get to 25GB per day. Such a onetime thing is nothing compared to that. Mind you that is all my drive but since my data hdd is rarely ever written too and then only ones those 344GB data written that activity monitor reports must be 98% on the SSD. And I don't do any kind of work that requires big files. Most of that is just websurfing and whatever OSX does. Page outs are at 4GB and swap at 1GB. 13 day uptime.

    Your solution is still easier because OSX disables the delete empty space solution with an SSD so people don't use it all the time. In in old Apple tradition they don't allow you to use it anyway if you want to use it once and know what you are doing.
     
  13. Weaselboy, Apr 27, 2013
    Last edited: Apr 27, 2013

    Weaselboy Moderator

    Weaselboy

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    #13
    I'm not sure why you seem to think I am disagreeing with you. I said "very very minimally" (two verys! :)) and went on to say it was "Not a big deal...".
     
  14. dusk007 macrumors 68040

    dusk007

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    #14
    Well I was pointing at the oddity of calling that hurting an SSD or causing damage. It is like saying driving with a car for a couple Miles does damage the engine or hurts the engine. It is somewhat misleading vocabulary IMO.
     
  15. Weaselboy Moderator

    Weaselboy

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    #15
    Okay... whatever you say. Sounds like you just want to argue.
     

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