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Discussion in 'Electronic Design' started by [email protected], Jan 16, 2008.

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  1. Guest

    ME FOR MY BAD ENGLISH...........
  2. Guest

    It's pretty self explanatory, Core 2 DUO has two cores, Core 2 QUAD
    has four cores.
  3. GregS

    GregS Guest


  4. Guest

    Windows XP on up, and modern Linux kernels should.

    On XP, type Ctrl-Shift-Esc and click on the Performance tab. You
    should see TWO windows (for a dual core chip) under CPU Usage
    History. Dunno if that works for quad cores.

  5. Guest

  6. qrk

    qrk Guest

    Win2k also supports multiple processors.
  7. Jim Thompson

    Jim Thompson Guest

    Does it really improve performance, or is it simply a marketing

    ...Jim Thompson
  8. TheM

    TheM Guest

    In real life it makes a big difference when you're doing several things at the same time.
    Say unzipping a large archive while doing something else.
    When I had a single-core cpu compacting messages in OutlookExpress rendered my PC
    useless, now I can do that in the background while I do something else.

    General feel while using a multi-cpu computer is definitely much better, however
    I think going beyond 2 probably does not make much of a difference, if any.

    Other than that, the only applications that make use of multiple processors directly
    are some graphics programs, some video editing software and 2-3 advanced games.

    And yes, Seti runs much better, almost 4x faster for a quad cpu :)

  9. Joel Koltner

    Joel Koltner Guest

    There is a real improvement, but it depends largely on...

    1) Do you tend to run multiple programs that are both CPU intensive at the
    same time?
    2) If not, do you have any single programs that are multi-processor aware and
    internally divide their workload between them?

    With two cores you don't usually get very close to 2x performance in "real
    world" applications -- 1.75x is considered very good. With four cores getting
    3.5x performance is doing quite well...

    There are some multi-threaded (able to use more than one core simultaneously)
    SPICEs out there (e.g.,,
    although AFAIK they've always been in the realm of more
    exotic/high-end/"developmental" SPICEs.
  10. GregS

    GregS Guest

    I'm installing an acquisition system that can make use of two processors. The guy
    programmed it that way. I understood that in Win2K you had to use a program that
    was programmed for two processors.

    So it seems what I'm, hearing is that in XP, ANY program will be split as necessary
    between processors ??

  11. Joel Koltner

    Joel Koltner Guest

    No; WinXP is still the same as Win2K in this regard.

    A program consists of one or more threads. Unless specifically told not to,
    Win2K/XP/etc. will schedule *threads* across multiple CPUs. The scheduling
    algorithm tries to be smart, though, and *usually* the same thread ends up on
    the same CPU, the idea being that there's a great likelihood of cache hits if
    a thread executes on the same CPU as it did previously, even if some other
    process's thread was scheduled inbetween. (Although again here a program can
    tell the scheduler that is has no "affinity" for a particular CPU if it likes
    and adjust a few other scheduling parameters.)

    In general there's no way of automatically splitting program execution at a
    finer level than that of threads because it becomes effectively impossible (at
    least, "on the fly") to figure out the dependencies between different parts of
    a thread (e.g., what parts can be executed in parallel, which depend on the
    order of execution, the availability of prior results, etc.).

  13. Or in fact, do you run one program and want to see its output at the same time?
    Display rendering is a heavy task, and having 2 CPUs enable the program to get
    on with things unrestricted by having to drive the display as well.

    More than 2 CPUs is overkill for a desktop, unless you use particular programs
    that take advantage of them.
  14. AZ Nomad

    AZ Nomad Guest

    That is only true if you're running a single tasking operating system.
  15. It depends on the program (or mix of programs). It's really nice when
    you have a single threaded calculation intensive program running, you
    can still work on a user application program without having to wait
    between keystrokes.

    Any well threaded application should be able to take advantage.
    Somewhat to my surprise I found Gravity (newsreader) makes good use of
    multiple processors (at least as of NT4 and I doubt it's changed).
    Seeing that it is able to pin two processors at times I'd be curious as
    to whether it could take advantage of more effectively.

  16. Guest

  17. qrk

    qrk Guest

    As others have stated, it makes a difference even if programs are
    mono-threaded and you're running them concurrently. Unfortunately,
    PSpice doesn't take advantage of muliple processors. LTspice, I
    believe, sort of does since the graphing portion is on a different
    thread than the solving portion. Xilinx's tools for compiling and
    routing FPGA stuff takes advange of muliprocessor environment with a
    very noticable improvement in completion time. Slowly, engineering
    apps are starting to use multiple threads. Multimedia programs like
    Photoshop and Vegas Video are multi-threaded.
  18. Guest

  19. qrk

    qrk Guest

    Ooops, error, Xilinx's tools don't support multiple processors yet. We
    got a major improvement due to memory speed (The old Athlon's had
    horrid memory transfer rates).
  20. krw

    krw Guest

    Xilinx' tools may not support multiple processors but a dual
    processor system doesn't turn to glue when doing P&R. I used to
    have two systems (one only for P&R).
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