How to erase a Crucial M4?

Discussion in 'MacBook Pro' started by Krazy Bill, Aug 18, 2012.

  1. Krazy Bill macrumors 68030

    Krazy Bill

    Dec 21, 2011
    Short story...

    I put Mountain Lion on my internal SSD temporarily (just to play with it). R/W Speeds were similar to those in Lion and Snow Leopard. Then a day later... I cloned back my workhorse and mainstay OS Snow Leopard from an external HDD back to the SSD and my speeds went to hell in a hand basket:

    Write was 250 MB/s. Now 150
    Read was 500 MB/s. Now 125 :eek:

    I've scoured the web looking for ways to bring my Crucial back to factory freshness but nothing's worked. (The Crucial forums are pretty much a crapshoot for OSX users).

    For the first time in over a year, I've used the TRIM enabler for a week now and that does nothing. (Never needed it before).

    I also left my SSD idle for 2 days hoping the Garbage Collection routines that Crucial uses would do their thing like they have the past year. No luck.

    So... how do I nuke my Crucial M4 back to factory goodness?
  2. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    Since you already have the TRIM hack enabled, you might want to try clearing unused blocks by running TRIM in single user mode.

    First start in single user mode by doing command-s when starting. Then at the resulting command prompt type "fsck -fy" (without the quotes). You will see a message that all unused blocks have been TRIMed. Type reboot. Done.

    Also, you might a safe mode once by holding the shift key when booting. Reboot once after the safe start. This erases some cached kext files and recreates them. Sometimes can help if you have been doing multiple OS version installs like you did.
  3. drambuie macrumors 6502a

    Feb 16, 2010
    Try deleting the partition with a reformat and reinstallation of Snow Leopard from scratch. I don't have first hand experience with this, but have read tech info to the effect that it is not advisable to clone partitions from HDDs to SSDs. Apparently SSD performance can suffer due to cluster misalignment.

    In your case it looks like the SSD may be taking two passes to read each cluster.
  4. Krazy Bill, Aug 18, 2012
    Last edited: Aug 18, 2012

    Krazy Bill thread starter macrumors 68030

    Krazy Bill

    Dec 21, 2011
    @Weaselboy: I've done those things but can't remember if I ever saw the "blocks have been trimmed" message.

    Going to try again as soon as my backup clone is complete.

    @drambule: Crap, I hate to do that even though this is sound advice. It may come to that though.

    Update: Single user mode or safe mode did not work. Screw it. I booted from my clone and nuked the M4 (Just a normal "non secure" erase. Getting proper speed results on the M4 running the test from the external. (I should... there's nothing on it and it's just sitting there. :))

    Currently cloning the external drive back to my mac.
  5. Krazy Bill, Aug 18, 2012
    Last edited: Aug 18, 2012

    Krazy Bill thread starter macrumors 68030

    Krazy Bill

    Dec 21, 2011
    Well, other than a much longer boot time I seem to be back to normal read/write speeds:


    Strange. Just a simple erase of the M4 and subsequent restoration of the original drive contents did it. (via a Carbon Copy Clone).

    Thanks you two for chiming in to help. :)

    Final Edit: Duh K-Bill... set your startup disk to your mac and I bet your boot time will improve. :eek:

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