Could apple do this?

macmax

macrumors regular
Original poster
Sep 5, 2002
209
0
caribbean
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
 

BenderBot1138

macrumors 6502
Oct 28, 2002
439
0
SHHHHHHH!!!!!!!

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

;)
 
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LethalWolfe

macrumors G3
Jan 11, 2002
9,368
119
Los Angeles
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
 
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firewire2001

macrumors 6502a
Apr 2, 2002
718
0
Hong Kong
Originally posted by LethalWolfe
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.
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.
 
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robbieduncan

Moderator emeritus
Jul 24, 2002
24,873
219
Harrogate
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.
 
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Chaszmyr

macrumors 601
Aug 9, 2002
4,266
76
Originally posted by robbieduncan
And I believe that the G4 does not work too well with more that 2 processors.
There are linux servers that use up to 8 G4s if I recall correctly.
 
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Jimong5

macrumors 6502
Jul 22, 2002
296
0
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!
 
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FattyMembrane

macrumors 6502a
Apr 14, 2002
966
154
bat country
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.
 
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macmax

macrumors regular
Original poster
Sep 5, 2002
209
0
caribbean
Originally posted by BenderBot1138
SHHHHHHH!!!!!!!

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

;)
hahhahahahaahhahha:D
 
Comment

macmax

macrumors regular
Original poster
Sep 5, 2002
209
0
caribbean
Originally posted by FattyMembrane
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.
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
 
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Stelliform

macrumors 68000
Oct 21, 2002
1,721
0
Originally posted by firewire2001



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

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.) :)
 
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pianojoe

macrumors 6502
Jul 5, 2001
452
15
N 49.50121 E008.54558
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...
 
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robbieduncan

Moderator emeritus
Jul 24, 2002
24,873
219
Harrogate
Originally posted by pianojoe
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...
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.
 
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Sun Baked

macrumors G5
May 19, 2002
14,859
57
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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