A question about SSD and RAM

Discussion in 'Mac Basics and Help' started by RedCroissant, Jul 22, 2012.

  1. RedCroissant Suspended

    Joined:
    Aug 13, 2011
    #1
    This might sound ridiculous to some people, but I would like some clarification or correction of my understanding of the similarities/differences of RAM and SSD storage.

    I remember a friend of mine when I was in the Navy using a RAM module to boot up Windows XP and he said that he used RAMdisk(or some other application) to do this. If RAM could be used to store the OS and be made bootable, could the a SSD be partitioned to be used as RAM and local storage so that one could easily repartition it as the need for more RAM arises?

    COuld it also b used to get rid of the RAM modules altogether and just rely on the SSD for both purposes?

    Thanks or your time!
     
  2. Office Hours macrumors member

    Joined:
    Jul 17, 2010
    #2
    RAM is much faster. They serve a specific purpose.
     
  3. RedCroissant thread starter Suspended

    Joined:
    Aug 13, 2011
    #3
    Ok. So if RAM is much faster but can also be used as a storage medium, wouldn't it be possible to make a RAM module that could serve as both? Wouldn't that mean a faster overall computer?
     
  4. chown33 macrumors 604

    Joined:
    Aug 9, 2009
    #4
    It would also be quite a bit more expensive (RAM chips cost more per bit), and substantially more power-hungry (RAM chips consume more power per stored bit).
     
  5. LostSoul80 macrumors 68020

    LostSoul80

    Joined:
    Jan 25, 2009
    #5
    The problem is the cost of RAM modules.
    You can google "swap files" to get some relevant information about memory management.
     
  6. phrehdd macrumors 68040

    phrehdd

    Joined:
    Oct 25, 2008
    #6
    Your question is a very good one and one that has been around for a long time.

    In the days of DOS, the use of RAM for a volume space was played with quite successfully. The limitation being the amount of RAM that could be used with a given computer. I remember introducing a programmer to a "RAM disk" to compile his work and the results for him was astounding in terms of speed.

    What is involved is taking a portion of the RAM and using it as a disk volume. There were and perhaps are some companies still around that would sell special cards loaded with RAM chips, hardware/firmware and a small battery. These units would fit in a slot of a PC and become another volume that could be exploited. For graphics this was great as a 'scratch disk' etc. For programmers, CAD and other disk intense work it would shave literally hours off their work back then.

    The biggest problem with using RAM is that it is volatile. When there is no electricity there is no memory and that means everything stored in RAM is gone. This is why small batteries were used with physical RAM disks/cards. When the computer was off, the battery would retain the information.

    The real challenge has to do with the operating system. For Windows back when, they had a swap file that could grow as needed or be a static size. The latter proved to require less overhead. Some people would make RAM disks to replace the swap file as it became clear that Windows (no matter what MS said) would swap out even when their was RAM available in normal usage. The RAM disk proved to speed up productivity on many RAM/drive intensive applications.

    I have never used a RAM disk with a Mac. I am sure there are others who could speak more about how to set up one. If you opt for a physical RAM disk (card), it most likely would be at least 3x as much as an SSD and also be limited to the bus speed of your machine. - 120 SSD vs 32 gig RAM drive card.

    For me, I rather get 2-3 quality SSD and stripe them (and use a typical hard drive = to the stripe volume as an asynchronous backup) than bother with RAM drives. The only time a RAM drive to me makes sense is again something like compiling programs or generating extremely complex design.

    Just my two cents.
     
  7. RedCroissant thread starter Suspended

    Joined:
    Aug 13, 2011
    #7
    Thanks a lot for this response! I don't think I would try this with my Mac or anything but I think I might try it with an older PC that's still running XP to see how it works and mess around with things.

    It's good to know that anything stored on a RAMdisk is gone once the power is turned off because I would have hated to find that out the hard way.
     
  8. phrehdd macrumors 68040

    phrehdd

    Joined:
    Oct 25, 2008
    #8
    I am glad if my few words helped. I do very much appreciate your thinking and trying to think outside the box.
     

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