Can some1 please SCHOOL ME on what a "RAM Disk" is? should I be using one?

Discussion in 'macOS' started by lip5016, Oct 21, 2014.

  1. lip5016 macrumors regular

    Jul 11, 2014
    Can somebody please tell me what a "RAM Disk" is, and if I should be using one?

    I was looking on the internet about how Apple used to have this "RAM Disk" thing in their old Mac's before eventually doing away with this feature.. I'm no expert on the subject, but it sounds like you can use a chunk of your harddrive space as RAM?

    This sounds pretty sweet, but I was also reading that the information created when you make one of these things can easily be lost.. I'm a performance junkie, so I always love the allure of improving my machines, but not at the expense of losing important information..

    1. Can somebody please tell me what this whole "RAM Disk" concept is about?

    2. Should I be using a "RAM Disk" when I do work in Logic X or w/music in general?

    3. What are the benefits of a "RAM Disk"? (Any negatives?)

    4. How much do they really improve performance?

    5. How big should you set your RAM Disk size? (to avoid memory paging) I've read that you should use no more than 50% of your total RAM as your maximum sized RAM Drive.. Thoughts?

    6. How do you even use a RAM Disk? Do you just make it and let it sit there while it does the rest? What do you do when you want to close it or turn off your computer or something to avoid data loss?


    oh yeah, also, i got this app thing too.. not sure what size to try out? should i bother messing with a RAM Disk at all?

    Screen Shot 2014-10-21 at 9.48.10 PM.png

    Thank you!! :D
  2. 556fmjoe macrumors 65816


    Apr 19, 2014
    Actually, it's the opposite.

    Normal storage volumes, such as your disk partitions, take a chunk of your hard disk, format it with a filesystem, and can be mounted by the OS for reading and writing. A RAM disk is simply a storage volume that takes a chunk out of RAM rather than the hard disk. This has benefits and drawbacks.

    RAM is tremendously fast. If you are performing a disk intensive operation, writing to or reading from RAM is many times faster than doing the same with even the fastest SSD.

    The downside is that RAM is volatile storage; everything is gone after a reboot. Any files you save in a RAM disk will not be there like they would be on a persistent storage volume (i.e. hard disk partition, USB drive, etc). This means that if you used a RAM disk to store some data that you needed to keep long term, you'd need to make sure you saved it to the hard disk before rebooting or dismounting the RAM disk.

    RAM disks are sometimes used for entire operating systems, such as Puppy Linux. This allows incredible performance, but you have to make sure you save anything you want to keep to a hard drive or other persistent storage.
  3. crenz macrumors 6502a


    Jul 3, 2003
    Shanghai, China
    Probably not. The only usage I could imagine is to use the RAM disk to store sample data (e.g. for EXS24 or Kontakt). This would make opening projects with a lot of sampled instruments much faster. However, as soon as you power off the computer, the data of the RAM disk will be lost. Therefore, you would need to make a little script to copy your samples over to the RAM disk every time you boot. It would only make sense if you switch between a lot of projects that all contain the same samples... not the way most people use Logic X, I guess.

    I would certainly never store recordings there - any power failure, and all your data will be lost.

    These days, I would just go for using SSDs for everything.
  4. PSB136 macrumors member

    Oct 26, 2014
    RAM Disks are literally that: your computer's RAM used like a disk drive. It's immensely faster than both mechanical disks and SSDs.

    Some people point their web browser cache to use a RAM disk so that pages can reload instantly, and also because visited websites won't be retained when the computer is shut down.

    Others set their Photoshop working cache to it, to make Photoshop work faster. Same with video editors. Basically, any app that requests a hard drive working directory can be set to use a RAM disk to make that app fly.
  5. aaroman macrumors newbie


    Jan 16, 2013
    No longer necessary

    The RAM Disk was a great idea -- back when we had 8, 16, and even 32 bit processors.

    Now, with 64 bit processors and gigabytes of RAM coming stock in your Mac, they are no longer needed. The OS is smart enough to read in as much of your file(s) as is required by your program and store it in RAM by itself, without you dedicating valuable little- or un-used RAM to a RAM Disk. And the good thing is, when your program is done with the file that it's read from, it closes it, and the file is automatically flushed from RAM, making room for the next file, program, or temporary data store. Automatically by the OS. And OS X/UNIX is really good at managing memory and reading the entirety of a file in to help speed up your system.

    And you don't have to worry about picking and choosing the right files, tweaking the size of your RAM Disk, copying the files manually to your RAM Disk with every system boot... I think you get the picture.

    RAM Disks were great in the good ol' days. Not so much anymore.
  6. sjinsjca macrumors 68020


    Oct 30, 2008
    Back in the days of floppy disks (google those if necessary!) and slow hard disks, RAM disks made sense. They created an evanescent but comparatively fast emulated disk drive in RAM.

    These days such trickery only makes sense if you have a large amount of RAM and an application that otherwise would do a lot of disk I/O. Some old-timey database operations come to mind, but nowadays database applications and OSes are smart enough to buffer what they access into RAM anyway.

    Just to put it in perspective: I've benchmarked my 2014 Retina Macbook Pro as providing nearly 1 Gbps read/write throughput to its SSD. That's about what you could get from EDO RAM not that long ago. Pretty amazing progress. And my machine's 1TB SSD storage is quite a bit more capacious than any RAM configuration is going to provide you, unless you have IBM's Watson supercomputer sitting in your den or something.

    (The evanescent nature of RAM disks can also be helpful to cloak-and-dagger types who want to leave no trace of their activities on a machine. Some high-security builds of Linux set up shop in a glorified RAM disk, ensuring that nothing gets written to an actual physical disk.)

    So, don't worry about it. Today, RAM disks fall into the "if you don't know what it is, you don't need it" category, and even if you knew what they were walking in the door, you almost certainly wouldn't need them today.
  7. poiihy macrumors 68020


    Aug 22, 2014
    RAM disks may be useful for minecraft and minecraft worlds.
  8. SlCKB0Y macrumors 68040


    Feb 25, 2012
    Sydney, Australia
    You must be a computer scientist or somethin...
  9. T'hain Esh Kelch macrumors 601

    T'hain Esh Kelch

    Aug 5, 2001
    Unless you are Marty McFly, before you come back this year, then no, you'd never need in these days. I/O is waaaay faster now.
  10. SlCKB0Y, Jan 12, 2015
    Last edited: Jan 12, 2015

    SlCKB0Y macrumors 68040


    Feb 25, 2012
    Sydney, Australia
    Huh? Not that long ago? You don't think nearly 20 years is a long time relative to the advances in computers?

    20 years ago, a 486 with Windows 3.1 or DOS was very common but within the year people would be buying 66Mhz Pentiums with EDO RAM and Windows 95 to browse the web using Excite on their 28.8k modems. Linux was a few years old and barely functional, Steve Jobs was at Pixar and Apple was going down the toilet.

    Yea, hardly anything has happened since then. :rolleyes:

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