Run your Mac up to 40 times faster with RamDisk

Sections: iMac, Mac mini, Mac Pro, MacBook Air, MacBook Pro, Macintosh/Apple Hardware, Originals, PowerBook

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Once upon a time (specifically, for about a year between buying my first laptop in 2006 and the Internet’s October, 1997 arrival in my neck of the (literal) woods) I ran the PowerBook 5300 about 95% on a RAM disk.

PowerBook 5300

During that interval, I was conducting my freelance writing business via FAX and snail mail. With a GlobalFax PC Card FAX modem, a barebones install of Microsoft Word 5.1, and a stripped-down configuration of Mac System 7.5.3, I was able to run pretty much all of the time off the RAM disk, even though the PowerBook had only 24MB of RAM installed. That allowed me to keep the hard drive spun down most of the time, making for blessed silence save for the soft clicking of the keys. Every so often I would spin up the HDD in order to save work to disk, but the RAM Disk setup was reasonably stable, and I lost very little work due to crashes and hangs. Indeed, it was probably more stable than the full System 7.5.3 running off the hard drive.

Aside from the benefit of near silent computing, the advantages of using a RAM disk were speed and longer battery runtime. Whatever the PowerBook 5300’s virtues (it did have some), speed wasn’t one of them, so every little bit helped. The processor—in that case a 100 MHz Power PC 603e—could reference RAM a lot faster than the 4,200 RPM HDD, and used less battery juice doing it. However, once the Internet arrived here in October, 1997, RAM disk running was pretty much over, at least for everyday computing, and interest in RAM disks began to fade. Apple dropped the Mac OS RAM DIsk creation option from OS X.


However, Swiss developer Power APP has just announced the release of RamDisk for Mac OS, a new utility that the company claims can speed up a Mac by factors of up to 40x, as well as increasing the lifetime of your MacBook’s Solid State Disk. As in days of yore, RamDisk creates a virtual drive using the Mac’s RAM, and, of course, today’s Macs give you a lot more RAM to work with. The virtual RamDisk drive can be treated like any drive on the Mac; files and data can be stored, and applications can be installed and run off that drive (although note well that until created data is saved to a physical volume it remains in a perishable state, and will be lost in the event of a power cutoff or unrecoverable crash). Under normal circumstances, an image of your virtual drive is stored on the SSD or hard disk of the Mac when it is shut down, and it is re-read at the next startup.Power APP recommends using RamDisk for two types of applications:

  1. Anything that makes extensive use of the SSD, executing a lot of writing cycles.
  2. Applications where speed is important, that make you wait during completing a task.

Solid State Drives (SSD) are faster than conventional hard disks (their mechanical counterpart), but since they are using flash memory for data storage, they have a limitation to the maximal number of possible write cycles. While this limitation is a fairly high number, some applications do a lot of shuffling data on the storage drive, and this process becomes more intensive as free space on the drive diminishes, further increasing the number of read/write cycles, which means a decreased lifespan for the SSD. Ram disks are even faster than SSDs.

According to Power APP’s General Manager, Christian Schaffner, they developed RamDisk for internal use after killing several SSDs before their expected lifespan. “We are using a bunch of MacBooks for several purposes, like iOS app development and picture editing,” Mr. Schaffner notes. “For better performance our MacBooks are equipped with SSD. And some of these SSD were dead way faster than we expected. We decided then to move the load away from the SSD to the RAM by creating a virtual drive in the RAM, installing applications directly in this virtual drive. This has two effects. Data shuffling is happening in the RAM and not on the SSD, increasing the speed drastically. Writing cycles on the SSD are heavily reduced, which increases the lifespan of the SSD. Now that we have been using RamDisk for ourself without problems we decided that this tool is ready to be sold.”


PowerAPP recommends that a RamDisk should not be bigger that 50 percent of available memory (although I used to get along fine on that old PowerBook 5300 setup using 16 of that machine’s total 24 MB of RAM for my RAM disk. However, the Power APP warns that if your RAM Disk is too big, your OS won’t have enough RAM to breath with freely, which will have an impact on performance. How much RAM your application needs depends pretty much on the application itself. Heavy picture editing with Photoshop will need more RAM than a browser does, for example.

Summary of RamDisk Features:

  • Systems with a mechanical hard drive will become faster, and systems with SSD will reduce the wear on the SSD
  • Create / remove Ram Disk easily
  • You can specific size, name
  • Auto-Mount Ram Disk Function in program startup
  • Booting Mac faster than from SSD
  • Generating temporary folders
  • Increase the lifetime of the SSD
  • Configure up to 75% of your available RAM to a RAM Disk
  • Create Snapshot Images of your RamDisk configuration
  • Configure Start Up and Shut Down Options
  • Configurable auto save
  • Choose individual names for the Ram Disk

RamDisk for Mac OS is available for $8.99 (USD) and works on OS X 10.6 or newer. It is sold exclusively at Power APP online.

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  • Mac Daily

    OS X users can create RAM Disks via the Terminal app for free.

    Open Applications > Utilities > Terminal and enter the following command:

    diskutil erasevolume HFS+ ‘RAM Disk’ `hdiutil attach -nomount ram://xxxxxxx`

    Replace the “x” characters above with the number that represents the desired size for your desired RAM Disk. The size of the disk is based on the number of 512-byte sectors. So, to create a 4 GB RAM Disk in OS X, replace the xxxxxxx’s in the Terminal command above with 8388608 which is the result of (4 * 1024³)/512.

    Run the command and you’ll have a 4GB Ram Disk (or whatever size you desire/can afford out of your system’s RAM) mounted on your desktop.

    Run apps via RAM and watch them fly! (Or, when you want to show just how fast your Mac is via something like Geekbench, you restart your Mac, create a Ram disk, and run Geekbench off RAM.)

    To remove the RAM Disk, just eject it via the Finder as with any other disk.


  • David Flory

    tried to buy the Ramdisk app. It wouldn’t accept my purchase as I could not enter state in the form. also unable to find any way on the site to let them know this. Not terribly professional looking.

  • http://ContactingPowerAPP Power APP

    Hi David

    Here are some possibilities to contact us, taken directly from the link that is listed in the article (you just have to click on one of them):
    Alternatively you can contact us vie twitter or facebook, the social buttons are spread all over the page …
    On the product site there are more social buttons where we can be reached.

    You could also follow the help link for more options to contact us.
    In case you entered the wrong state, it’s no problem to correct that afterwards.

    To send you the app an e-mali adress is sufficient.

    Thank you for your comment and best regards
    Christian Schaffner

  • Power APP

    Thank you for the comment.
    Of course you can create a RamDisk via command line every time you need it.
    With RamDisk for Mac you are able to make an image of it and autoload it on your next start, you can also create several RamDisk profiles, optimized for different applications.
    And of course you have auto save/auto load features for start up and shut down.
    It’s more than just a bit more comfortable than a command line, our devs would have done that otherwise.
    Best regards
    Christian Schaffner

  • Britt Blaser

    Any thoughts on speeding up and Spotlight? Can apps and their data files be in the ramdisk?



    – i found set up very unclear
    – they are Swiss – German and their English is very confusing

    – Most of the time there is no tech support available