G5 2.5 and Photoshop CS memory

Posted:
in Current Mac Hardware edited January 2014
My new G5 2.5 w/ 2 gig of RAM (OS 10.3.5) only shows 1853 MB of available RAM in Photoshop. I understand Panther varies the amount of RAM to applications. Is that why or do I have a bug somewhere?

Comments

  • Reply 1 of 11
    mattyjmattyj Posts: 898member
    The rest of the memory is probably been used to keep the system itself running, OS X is basically an application just like CS, so it does need RAM in order to run. Plus CS is a 32bit application which means it can only use up to 2GB of RAM, however very few apps use the upper most limit for RAM, plus you have to take into account mac OS X.
  • Reply 2 of 11
    Quote:

    Originally posted by mattyj

    The rest of the memory is probably been used to keep the system itself running, OS X is basically an application just like CS, so it does need RAM in order to run. Plus CS is a 32bit application which means it can only use up to 2GB of RAM, however very few apps use the upper most limit for RAM, plus you have to take into account mac OS X.



    That's all wonderful but on my G4 w/ 1 gig of RAM and exactly the same OS Photoshop CS showed 1 gig of available RAM. The G5 2.5 starts at 512 mb of ram so obviously the OS isn't using anywhere near my 2 gig. It has to be something else.
  • Reply 3 of 11
    mattyjmattyj Posts: 898member
    From what you said 2000MB minus 1853MB equals 147MB. That means that photoshop is using 1.8Gigs whilst the system and all other threads is having to make do with 147MB which isn't all that much. So what's your beef? Only 1853MB is available in photoshop as the rest is used by the system.
  • Reply 4 of 11
    Quote:

    Originally posted by mattyj

    From what you said 2000MB minus 1853MB equals 147MB. That means that photoshop is using 1.8Gigs whilst the system and all other threads is having to make do with 147MB which isn't all that much. So what's your beef? Only 1853MB is available in photoshop as the rest is used by the system.



    I'm guesssing you have no experience with Photoshop.
  • Reply 5 of 11
    mattyjmattyj Posts: 898member
  • Reply 6 of 11
    Quote:

    Originally posted by mattyj

    From what you said 2000MB minus 1853MB equals 147MB. That means that photoshop is using 1.8Gigs whilst the system and all other threads is having to make do with 147MB which isn't all that much. So what's your beef? Only 1853MB is available in photoshop as the rest is used by the system.



    This makes absolutely no sense. None. Zero.



    You said:



    "That means that photoshop is using 1.8Gigs whilst the system and all other threads is having to make do with 147MB which isn't all that much"



    Then my friend you reverse yourself:



    "Only 1853MB is available in photoshop as the rest is used by the system."



    From your previous post:



    "The rest of the memory is probably been used to keep the system itself running, OS X is basically an application just like CS, so it does need RAM in order to run."



    So tell me Mr. Wizzard, how do the G5 2.5 w/ 512 mb of RAM function at all if the OS needs 1.8 gig of RAM to operate "the system"?
  • Reply 7 of 11
    slugheadslughead Posts: 1,169member
    Quote:

    Originally posted by 1douglask

    So tell me Mr. Wizzard, how do the G5 2.5 w/ 512 mb of RAM function at all if the OS needs 1.8 gig of RAM to operate "the system"?



    Uh OS X will use whatever RAM it can to assist in caching file listings, settings, and everything else under the sun.



    If you open up activity monitor and list by memory usage, you can often see the window server gobbling up more and more RAM--caching commonly used directories into RAM for super-fast "file listing."



    I know from personal experience that 2.5GB RAM vs 512MB RAM (on my G5, at least) will speed up a system by at least 30% in file management and opening programs (because the window server doesn't need to dump anything to make room for the new program's variables).
  • Reply 8 of 11
    mattyjmattyj Posts: 898member
    "So tell me Mr. Wizzard, how do the G5 2.5 w/ 512 mb of RAM function at all if the OS needs 1.8 gig of RAM to operate "the system"?"



    The OS is the system. I did not say that the OS uses 1.8GB of RAM I said that PS CS was using 1.8GB of your system memory, and that Mac OS X (the system) is using the remainder, not the other way round.
  • Reply 9 of 11
    resres Posts: 711member
    Quote:

    Originally posted by 1douglask

    This makes absolutely no sense. None. Zero.



    You said:



    "That means that photoshop is using 1.8Gigs whilst the system and all other threads is having to make do with 147MB which isn't all that much"



    Then my friend you reverse yourself:



    "Only 1853MB is available in photoshop as the rest is used by the system."



    -snip-





    He is not reversing himself: Those two sentences have the same meaning. Read them again carefully (and remember 1853MB is approximately 1.8Gigs).
  • Reply 10 of 11
    I'm assuming that you've got Photoshop preferences set to use 100% of available memory? (Preferences->Memory and Image Cache...)



    My guess is that you're running up against the 2CB limit imposed by the fact that CS is a 32-bit application.



    Photoshop has to reserve sufficient memory in the address space for the executable code, stacks etc. (147MB) and the rest is available for CS to use. Whether or not it uses virtual meemory, you're up to the limit of what the application can use in a single process - i.e. to have 2GB available for images and cache, you would need 2GB+147MB which it can't address.



    On a 1GB machine, it still reserves the 147MB (or whatever), but still has address space available to use via virtual memory, so it shows the full 1GB as available.



    Hope that makes sense.
  • Reply 11 of 11
    mattyjmattyj Posts: 898member
    Yes that may be true, however to my knowledge no application can fully use 2GB or over of RAM when it's a 32bit application. Besides OS X still needs memory to run, what you're implying is that OS X doesn't need any RAM in order to run which isn't exactly how it works...



    I have CS and it can only see/use 643MB of my 768 memory - the rest of the RAM will be for the system. How your G4 could use up to all of your system RAM I do not know, and it shouldn't be able to.
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