Author: Dann Corbit
Date: 10:58:41 03/28/01
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On March 28, 2001 at 10:20:14, Christophe Theron wrote: [snip] >My first intention was simply to figure out what was a dual worth really. > >I did these computations for myself, then decided to publish it because I think >it's good informations for the CCC forum. > >It is true that I believe that adding chess knowledge in a program is more >interesting than making a program SMP, and that there is more evolution >potential in working on chess knowledge. > >And it is clear for me that multiprocessor computers will not be the mainstream >in the foreseeable future. > >I know that some will disagree, I can even guess who. > >These people are just ignoring facts of society like Internet mobile phones, >PDAs, tablet PCs and the like. I think you are wrong about duals. I imagine you may have guessed it was me. The reason I think so is that a dual (or quad -- whatever) is the cheapest way to get high throughput. As Eugene pointed out, a dual with an effective througput of 1200 MHz is better than a single CPU of 1200 MHz as well. We could just as well say, "Do not bother to upgrade from 500 MHz to 1GHz, since it will only add 50 ELO." This statement is completely true. But having a faster machine is very valuable for many other tasks as well. This machine is 960 MHz, and with 512 megs of ram and 100 gigs of hard disk. And yet I have projects that take over 1/2 hour to compile. At the cost of my time, the machine pays for itself over a slower one in a ridiculously short period of time. The future of fast computing will be multiple CPU's. It is absurdly easier to get a lot of computing power by SMP compared to increasing the frequency. And when the CPU's near 2GHz, and the traces .1 micron, how much will it cost to increase again by shrinking and speedup? Calculate the cost of a multiple CPU machine, and then calculate the cost of a single CPU machine with exactly the same throughput. You will find that the multiple CPU machines are a bargain. A workman is as good as his tools. Let's try an exaggeration. There are two equally skilled workers. One has a 286 with one meg of ram, the other has a dual CPU Athlon running at 900 MHz per CPU. Which one will get quality work done first? (Remember, I said that they were equally skilled). Now, any tool advantage one worker has over another will translate into more productivity. The cost benefit line is something for managers to calculate as to how far they are willing to go in beefing up the capital used by the work force. But if you are going to outfit people with high quality equipment, it makes great sense to use multiple CPU's. All that having been said, you are clearly right about CPU horsepower. The difference added by doubling the speed is only 53 ELO. So, if you take an old Pentium Pro 200 and put a chess program on it, and play that same program against a dual with 1GHz CPU's, the dual won't win 1000 out of 1000 games. The ELO difference would be roughly: (2000/200)*50=500 ELO and so the Pentium Pro will win 5% of the points. However, if you have a quad, it will only be .3% of the points (roughly speaking). So, your point is well founded. If you spend a bazillion dollars to get the "ultimate" chess machine, it won't dominate like some might imagine. But you could spend half a bazillion and get the same horsepower if you bought a 2 CPU machine instead. ;-)
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