Prevent SSD wear by using a RAM disk for cache

Apple Online Store“I was searching for ways to limit the wear of my SSD (since each cell has a limited lifetime with regards to writes). One solution was to store the Safari cache on a RAM drive which will only be written to disk at logout,” QuickSander reports via Macworld’s Mac OSX Hints.

QuickSander reports, “Several hints on this site describe a way to store Safari cache on a RAM drive. However, none seemed to work for me because some RAMdrive creators were not available for download anymore (EsperanceDV) [and] other scripts did not provide a way to store the cache to disk at logout.”

QuickSander reports, “Therefore, I created [a] Mac OS X application (which is actually a simple Bash script), which you can place in your login items which will create a RAM drive and store/restore Safari cache on login/logout… Actually you can store anything to the RAMdisk and the app will restore it on login.”

Full article here.


  1. “since each cell has a limited lifetime with regards to writes”

    Do you really think you’re going to reach the SSD’s read-write limit in your computer’s lifetime????

  2. @ ed malloy

    Yes, lots of gears actually.
    The more they turn, the shorter the lifespan of the SSD.
    That’s why it’s also a good idea to open up the SSD sometimes and oil ’em gears, to keep ’em churning.

  3. Many ssd’s (ones that are sandforce based among others) have thier own firmware that handles trimming without OS support.

    Check out the OCZ Vertex 2 – it autotrims and doesnt rely on OS support for trimming, plus it’s a very nice/fast ssd.

  4. I’ve been using SSDs for years now and I haven’t run into any memory problems.

    “…To get that very high speed the process will have to write big blocks (which also simplifies the calculation).

    We assume perfect wear leveling which means we need to fill the disk 2 million times to get to the write endurance limit.

    2 million (write endurance) x 64G (capacity) divided by 80M bytes / sec gives the endurance limited life in seconds.

    That’s a meaningless number – which needs to be divided by seconds in an hour, hours in a day etc etc to give…

    The end result is 51 years!

    But you can see how just a handful of years ago – when write endurance was 20x less than it is today – and disk capacities were smaller.”

  5. @Ballmer’s left nut.

    I recently did the research and purchased a SSD for my 2010 17″ MBP. Check the research and you will find that OS X outperforms TRIM on Windows in terms of maintaining performance on a “dirty” SSD. Clearly Apple is doing something better than M$ – no big surprise given the SSD driven MB Air and the broader move toward SSDs.

    I went with the OWC SSD with Sandforce because of the numerous benchmark reviews placing it at or near the top, and it is very cost competitive.

    What an incredible upgrade to my MBP!!!!!

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