One processor at a time?

Discussion in 'Macintosh Computers' started by believo, Nov 13, 2004.

  1. macrumors regular

    believo

    Joined:
    May 21, 2004
    Location:
    Los Angeles, CA
    #1
    I've heard that when working in a program, even though it's a multi-processor supported program, you are only using one processor at a time on that particular program. Is this true?

    I've also heard that while the G5 dual 2.0s have 8 ram slots. Four are used for one processor and four for the other. Is this true?

    thanks!
     
  2. macrumors 6502

    Joined:
    Nov 11, 2004
    Location:
    Denver, CO
    #2
    i belive that one processor handles current foreground programs, and one handles system idle processes and background programs.
     
  3. macrumors G5

    Sun Baked

    Joined:
    May 19, 2002
    #3
    Depends on the number of THREADS that the program creates.

    The OS manages threads, which can be run on either CPU (and in some cases the GPU.)
    Nope all the memory is hooked to Memory Controller and shared by both CPUs, it's not hooked to the CPUs -- what you are talking about would be for a NUMA architecture system, which we don't have yet (because there are NO integrated memory controllers.)

    Thats part of AMD's architecture.
     
  4. thread starter macrumors regular

    believo

    Joined:
    May 21, 2004
    Location:
    Los Angeles, CA
    #4
    for instance photoshop or final cut HD, do u know about these particular programs?

    thanks
     
  5. macrumors G5

    Sun Baked

    Joined:
    May 19, 2002
    #5
    Check out www.barefeats.com

    Considering some of the "filters" run twice as fast on duals as they do on singles would lead one to think that they take advantage of the 2nd CPU.

    Plus photoshop is one of the oldest multi-cpu capable applications on the Mac.
     
  6. macrumors 68030

    Catfish_Man

    Joined:
    Sep 13, 2001
    Location:
    Portland, OR
    #6
    Both of these programs are fairly heavily multithreaded. So are most 3D programs, Omniweb, and many others. These programs will use both processors at the same time. Some other programs will only use one, and the other processor will be used for other tasks running at the same time (and there are always other tasks running).
     
  7. macrumors 68030

    slooksterPSV

    Joined:
    Apr 17, 2004
    Location:
    Nowheresville
    #7
    Trace the traces from the RAM slots to the controller, then from the controller all the way back to the CPU, there's one way you can tell that, but seriously, it all runs on the same memory. On a multi-cpu system, 1 cpu won't handle a certain number of slots of memory, that'd just make the system sluggish. Especially if it was using the processor the memory was hooked up to the most. Nothing would honestly run that fast. OS X, would probably take 10 more seconds to load, Photoshop about 12 more seconds, and yeah just think of it like that. Like I said, you want to see it for yourself, trace the traces back and forth.
     
  8. macrumors 68020

    daveL

    Joined:
    Jun 18, 2003
    Location:
    Montana
    #8
    One thing's for sure, whatever your source was for the information stated above should not be viewed as authoritative ;-)
     
  9. macrumors 68030

    superbovine

    Joined:
    Nov 7, 2003
    #9
    no
     
  10. Jaz
    macrumors regular

    Joined:
    Sep 7, 2004
    Location:
    Sydney, Australia
    #10
    Yeah, most pro apps will be multi-threaded but you won't see it in Safari or Mail anytime soon.

    The real benefit for general use will be when ALL of the OS is multi-threaded. Some parts of OS X are not yet.
     

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