405 MB/s Transfer Rate!

Discussion in 'Mac Pro' started by wheezy, Aug 30, 2009.

  1. wheezy macrumors 65816

    wheezy

    Joined:
    Apr 7, 2005
    Location:
    Alpine, UT
    #1
    So just for fun I decided to make 2 RAMDISKS on my MacPro and see how fast I could move a file between them. Picked a HB'd movie of Seabiscuit (1.16GB) and moved it over from my Hard Drive to ramdisk1, took 5 seconds, squeezed out just shy of 200MB/s with my RAID0 (2 Samsung F1).

    Using the new screen record of Quicktime X I decided to record just how fast I could move the file from ramdisk 1 to ramdisk 2... 405MB/s, took 2.5 seconds to move the file.

    YouTube HD

    Even though it's HD, it's still hard to see since my original is a 1680x1050 Screen Capture. If you'd like to download the original QT file, Click Here.

    [​IMG]

    So, what does all this mean? Well, seeing as a RAMDISK will be erased the second the power goes off on the machine or you eject the drive, it doesn't mean a whooole lot. It was just a lot of fun. Other than setting them up for a scratch disk for PS, I don't know what you could really do that would make a effective use of that speed.

    -----

    If you'd like to give this a whirl yourself, just enter this code into Terminal:

    Code:
    diskutil erasevolume HFS+ "ramdisk" `hdiutil attach -nomount ram://1165430`
    1165430 = 550MB
    2330860 = 1.18GB

    To make a few of them, just give each one a different name.
     
  2. Infrared macrumors 68000

    Infrared

    Joined:
    Mar 28, 2007
    #2
    I'm surprised it's not faster. These guys get 2GB/s from an SSD RAID:

    http://www.youtube.com/watch?v=YmjJqJV1Wsk

    Surely memory transfers would be faster than that?
     
  3. alphaod macrumors Core

    alphaod

    Joined:
    Feb 9, 2008
    Location:
    NYC
    #3
    Sorry to say this, but it looks like you need faster RAM :p

    [​IMG]
     
  4. wheezy thread starter macrumors 65816

    wheezy

    Joined:
    Apr 7, 2005
    Location:
    Alpine, UT
    #4
    That's a yummy number, were you moving a file or does it just test it's own info?

    I can't really put in any faster RAM seeing as well... it's the spec it was made for.
     
  5. wheezy thread starter macrumors 65816

    wheezy

    Joined:
    Apr 7, 2005
    Location:
    Alpine, UT
    #5
    Well, I just found that AJA App and hit 1843.5 / 931.6, but the numbers are all over the place.
     
  6. wheezy thread starter macrumors 65816

    wheezy

    Joined:
    Apr 7, 2005
    Location:
    Alpine, UT
    #6
    I think if it were possible to span out the image over all the ram instead of 1 stick it would increase quite a lot. They're getting that cause of how many drives their using. If I were to make a 4GB image maybe it would speed up, I'm not sure how it writes the info - if it would do it like a RAID or not and spread the data out.
     
  7. Tesselator macrumors 601

    Tesselator

    Joined:
    Jan 9, 2008
    Location:
    Japan
    #7
    Data in memory IS interleaved. In dual channel mode across 2. In triple channel mode across 3 and in quad-channel mode across 4 but that's not available on Mac Pro's for now.
     
  8. Tesselator macrumors 601

    Tesselator

    Joined:
    Jan 9, 2008
    Location:
    Japan
    #8

    Sorry to say this, but it looks like you need faster RAM :p

    [​IMG]
     
  9. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #9
    That blows. What gives?

    BTW, on the bench data.... You're evil!! :eek: Makes my measly 1.39GB/s (mechanical disk) appear to drag @ss. :D :p
     

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