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Thread: ram available to PS?

  1. #1
    Join Date
    Jan 2005
    Location
    Dallas, TX
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    12

    Default ram available to PS?

    just installed 3 extra gigs of guru ram (3.5 total) in a new 2.5 dual, it all shows up in the system profile and seems to work ok. but in photoshop CS only 1779MB shows as available; even at 100%. now i know that PS can only use a little less than 2 gigs, but is 1779MB correct?
    thanks,
    pete

  2. #2
    Join Date
    Jan 2005
    Location
    Dallas, TX
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    Default way less than 2 gigs....

    adobe sez:
    "Photoshop can only use the first 2 GB of RAM on the computer. The operating system uses some of this RAM, so the Photoshop Memory Usage preference displays only a maximum of 1.6 or 1.7 GB of total available RAM."

    so if i set it at 70% of the 1779MB that equals only 1245MB.....

    guess it is time to run that PS speed test for myself, 70% vs 100%

    just talking out loud,
    pete

  3. #3
    Join Date
    Aug 2000
    Location
    Concord, CA
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    7,056

    Default

    pete,

    I only have a G4 with max possible 2GB of RAM. My tests in Pshop showed:
    Available RAM-1879MB (CS)
    Max used by Pshop-70%=1315MB (CS)

    But I do recall that on Boots' G5 with 4GB RAM, he was getting something less available RAM in Pshop CS than I did. I just don't recall how much less. Only he can tell us. k

  4. #4
    Join Date
    Aug 2002
    Posts
    1,010

    Default

    Pete,

    Your display of 1779MB available in PS prefs is entirely correct.

    Now here is the fun part:

    If I test with 2GB RAM installed in my machine, PS prefs says 1871MB available to PS, and with a 70% allocation, that yields about 1310MB max used by PS.

    If I test with 4GB installed in my machine, PS prefs says 1806MB available to PS, and with a 70% allocation, that yields about 1264MB max used by PS.

    You'd think the 1310MB max used by Photoshop would return a faster test result. Guess what. The opposite is true. The 4GB install returns a faster result by 5%! (a big difference in PshopTest).
    And the speed bump is all in opening a file and saving a file. So Photoshop benefits by way of the OS benefiting from the additional installed RAM.

    So far, I do not know if installing more than 4GB of RAM will show an even smaller 'available' figure. I haven't tested yet with more than 4GB in the machine.
    The 7MB difference of your 'available' of 1779MB in relation to my 'available' of 1806MB is probably due to you having either more startup items running, or you checked the pref panel with other apps running at the same time, or maybe you have a file already open in PS.

    I notice in my research the 'available' figure is at its maximum after a restart with nothing else opened or running...

    -------

    Now when it comes to "100%" allocation setting, don't assume that a faster result at the large file size will hold true for the small test file size. Results seem to indicate 70% is better for smaller files. But more research is necessary to pin this down. Stay tuned!

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