Re: A Question about Dual CPU systems

[Ed Troy <etroy@aeroconsult.com>]

I have been running a dual processor Pentium III for about 3 years now. It 
is only 600 MHz, but it blows the doors of another computer that I have, 
which is an 800 MHz Pentium III. The 800 MHz computer, however, has a 133 
MHz bus, and a faster generation of Pentium III, so I really expected the 
800 MHz computer to run faster, on any given task, at least. (Admittedly, 
the dual processor unit has ultra-wide, ultra fast SCSI drives, as opposed 
to regular drives, but I did not expect that to make much difference on 
data processing. I believe the reason for the speed is that the dual 
processor can basically devote all of one processor to number crunching, 
and the other one can take care of everything else.

I used to run both Linux and Win2K on that machine, but I now run just 
Win2K on it. The 800 MHz machine was originally supposed to be, primarily, 
a Linux box, but it ends up running Win2k most of the time, now, because of 
the one problem that I have had with dual processor (win2k at least) 
machines. I have had a lot of problems related to hardware stability and 
compatibility. For example, I cannot run Roxio Easy CD on the dual 
processor machine. It becomes unstable and gives frequent "blue screens of 
death". Also, some programs that use the Sound Blaster sound card cause the 
infamous BSOD. Creative Labs states that they do not support dual processor 
machines. Period.

As pointed out by others, any given program will not run faster with a dual 
processor, except to the extent that it does not have to handle other 
tasks, unless you run a multi-threaded application. Many of the high end 
applications, that make extensive use of computations, such as 
electromagnetic analysis and finite element analysis programs, do have 
multi-threading built in, or they have a version that is specifically 
compiled for that purpose. (Usually at a higher price.) Overall, however, 
for number crunching applications, you can't beat a dual processor, in my 
opinion. I have used multi-processor machines in both Linux and Win2K to 
process Seti@home files, and it makes a big difference. You can, 
effectively, get twice as much work done in a given time using a dual 
processor Linux box with Seti@home if you set up two independent 
directories, with two independent copies of the program. Then, you go into 
each directory and run the program. As long as each copy is totally 
independent, and does not "know" about the other, it works like a charm. I 
don't see any reason this "trick" could not be used to process the TASS data.

As far as sources for dual processor motherboards, I have always used 
Treasure Chest computers (http://www.tccomputers.com) for motherboards, 
chips, memory, etc. They have a dual processor Pentium Xeon that just 
became available for a few hundred dollars, which supports up to 4 GB of 
Rambus Ram. It requires a special case. As I recall, the price for a 
computer at 1.8 GHz, less hard drives, monitor, keyboard, and mouse, was 
about $2000 to $3000. This includes the two processors, special case,  and 
1 GB of ram. The motherboard has built in SCSI, 4X AGP video, and sound 
(not SoundBlaster) built in.

Hope this helps,
Ed

At 01:37 PM 5/9/2002, you wrote:
>Now that I am running production on the data, I am thinking about how to 
>make the process go faster.  I am thinking about a dual cpu mother board.
>
>I assume that such a system does not make the pipeline run faster.  Is 
>this true?  Seems to me that the code would have to know about the 
>available cpu and this would take a lot of special code.
>
>I assume that what a second processor would buy me is the ability to 
>simultaneously work on the data while the pipeline was running at little 
>loss of power.  Is this true?
>
>Does a dual cpu system make economic sense.  I.e. are they so expensive 
>that I would be better off running two computers and getting a network 
>going to move the data around?
>
>Anyone have any recommended place to buy a dual cpu bare bones system?
>
>Tom Droege
>