Could apple do this?

Discussion in 'General Mac Discussion' started by macmax, Nov 11, 2002.

  1. macmax macrumors regular

    Joined:
    Sep 5, 2002
    Location:
    caribbean
    #1
    What if instead of giving us a mac with a g5 they give us a mac with multiprocessors,let's say 3 or four g3's or g4's.

    with the g3's the cost would come down to a minimun and still the machine would be really ,really fast, probably more than with a beefed up g5.

    Would someone explain to me why the bus is still thos slow, does this affect the overall speed machine , and how does it do it>?

    Thanks
     
  2. BenderBot1138 macrumors 6502

    Joined:
    Oct 28, 2002
    #2
    SHHHHHHH!!!!!!!

    I'm still trying to buy up the world's ebay supply of G3 machines to make the worlds first 1000 processor cluster.

    ;)
     
  3. LethalWolfe macrumors G3

    LethalWolfe

    Joined:
    Jan 11, 2002
    Location:
    Los Angeles
    #3
    1. The problem w/multiproccessors is that not very many programs support them. So, while a few proggies w/multiproc support would be very fast, the other 99% of software would be slow as hell. Not to mention more procs means more heat, and more space has to be made for them.

    2. Why is the FSB still so slow? Who knows.

    2a. Does it effect the overall speed of the machine? Yes.

    3a. How? In short, the FSB is the channel of communication between the proc and the RAM, so the faster the FSB, the faster the data gets transfered, and the faster things will get done.


    Lethal
     
  4. firewire2001 macrumors 6502a

    Joined:
    Apr 2, 2002
    Location:
    Hong Kong
    #4
    hrm. not neccassarily so.

    though this scheme isnt very practical, it is possible.

    an os can be reconfigured to route processing to more than one processor without programs having special code.

    at heart, it is an interesting idea, but is impractical due to the fact that many programs already take advantage of multiple processors and would be rendered incompatible with such a scheme.
     
  5. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #5
    I'm not totally sure about this, but I don't think that the G3 support SMP, only the G4. So no multiprocessor G3's. And I believe that the G4 does not work too well with more that 2 processors.
     
  6. Chaszmyr macrumors 601

    Chaszmyr

    Joined:
    Aug 9, 2002
    #6
    There are linux servers that use up to 8 G4s if I recall correctly.
     
  7. Jimong5 macrumors 6502

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    Jul 22, 2002
    #7
    it doesnt matter if an app is SMP aware of not. On my Daul G4, bIt sorts out apps, so I could run 2 apps as weel as a single 867 could run 1. OS X figures out how to do this, and sometimes even splits the threads by itself!
     
  8. FattyMembrane macrumors 6502a

    FattyMembrane

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    Apr 14, 2002
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    bat country
    #8
    if i'm not mistaken, IBM's sahara g3 (the one in the new ibooks) is capable of 1ghz+ clock speeds, very high bus speeds, ddr ram, and smp (unlike earlier g3 processors). of course, if apple introduced a dual 1.25 ghz ibook with a 200mhz bus and full ddr ram, no one would buy the powerbook (the g4 does not have the capacity for the bus and full support of the ddr ram). so the ibook is being "dumbed down" because of the lackluster performance of moto's g4s. i've probably made some glaring errors, so feel free to correct them :) .

    although you would miss out on altivec, a well cooled machine running 4 1ghz+ g3s with true ddr ram and a decent bus speed would knock the socks off of a new mirrored door dualie, and would have a much lower relative cost.
     
  9. idkew macrumors 68020

    idkew

    Joined:
    Sep 26, 2001
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    where the concrete to dirt ratio is better
    #9
    actually, i recall the number 16 as being the top.
     
  10. macmax thread starter macrumors regular

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    Sep 5, 2002
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    caribbean
    #10
    hahhahahahaahhahha:D
     
  11. macmax thread starter macrumors regular

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    Sep 5, 2002
    Location:
    caribbean
    #11
    my cousin is an engineer and he said they where working with a cluters , which i don't know what it is, and they got terrific results.
    Also the cost would be really low
     
  12. Stelliform macrumors 68000

    Stelliform

    Joined:
    Oct 21, 2002
    #12
    As long as the application is MultiThreaded, the threads can be separated amoung as many processes as the OS handles. (If I remember my CMPS 451 correctly.) :)
     
  13. pianojoe macrumors 6502

    pianojoe

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    Jul 5, 2001
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    N 49.50121 E008.54558
    #13
    Putting more than one processor on a single mobo means that they have to share the memory and the bus which is costly in terms of performance. Even if the software distributes processor usage evenly, the performance gain with 4 processors will not be 400%, but roughly a mere 250%.

    O.K., better than nothing, but...
     
  14. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #14
    This is true of current motherboards. It does not have to be the case. The upcomming AMD Hammer series will not have this problem. Each processor will have a point-to-point bus to tbe memory (with a memory contoller on the chip). So you get much better scaling with the number of processors.
     
  15. Sun Baked macrumors G5

    Sun Baked

    Joined:
    May 19, 2002
    #15
    The G3 does not support multiprocessor configutations and in attempts to reduce costs and fix cache problems - the G4 now only supports a dual CPU configurations, anything else is messy, and Motorola's core market (embedded) doesn't care about anything more.
     

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