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Subject: Re: Does 64 bit architecture have any benefit on chess programs?

Author: Vincent Diepeveen

Date: 11:54:13 10/02/02

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On October 02, 2002 at 14:23:53, Tom Kerrigan wrote:

>On October 02, 2002 at 11:56:11, Vincent Diepeveen wrote:
>
>>Most supercomputer processors are stupid alpha's or stupid other cpu's
>>which run
>>  a) at lower Mhz speeds
>>  b) give lower performance
>
>Wait a minute, something just occurred to me. What clock speed does the Alpha
>run at? 1.25GHz. What clock speed does McKinley run at? Last I heard, 1GHz, at
>most. So not only are you wrong on the performance count, you're also wrong on
>the clock speed count.
>-Tom

I do not know a single supercomputer with alpha 21264 at 1.25 Ghz. Correct
me if i'm wrong. If i browse around at top500.org i see:

3 alpha 1 Ghz
4 alpha 1 Ghz
6 alpha 1 Ghz
37 alpha 1 Ghz
38 alpha 1 Ghz

I'm not seeing a single one clocked higher than 1 Ghz.

Also the alpha is dead. the McKinley takes over!

For me Mckinley is way faster than alpha. Alpha 21264c for me is
slower than K7. Not much. But still. McKinley is 33% faster.

That's without optimizing for 64 bits yet, where both alpha + mckinley
will profit.

though it won't bring much :)

Look at specs:
  alpha    : 4 instructions a clock
  mckinley : 6 instructions a clock

So *potential* the mckinley is 50% faster. Of course that never
will get achieved, we must be realistic. Doing more than 6 instructions
a clock is really nonsense for chess.

We still didn't talk about things like branch mispredictions. The alpha
has very big penalties for a branch misprediction. i don't know about
mckinley but seeing the results i had at the 2 cpu's i bet the mckinley
is either having less or handling it better somehow.

So i don't know what you care for, but i care for what i have SEEN. I see
that the mckinley is with an edition 1.0 compiler already way faster than
any other cpu i ever have seen.

Now i don't know how hard guys like nalimov work, but obviously the
intel c++ team that made that cross compiler which i used to benchmark
diep on mckinley, they have a big disadvantage in time compared to the
alpha team who already could work on the alpha compiler for a quarter
of a century or so (?).

Very obviously that is very promising for newer editions of their thing.

The achieved results i have for the mckinley (so the 33% faster results)
i did about half a year ago at a mckinley with a intel c++ 5.01 cross
compiler which compiles for the itanium 1, not the itanium 2.

I can list another set of disadvantages for the mckinley. I don't care.
the important thing is that it's faster. the measurement is 33% faster. it
was a very *accurate* measurement. Within the 1% limit even.

The machine was completely idling when doing this test.

It tells me that the thing could get way faster for me by optimizing and
using newer compiler editions. When was intel c++ 5.01 released, long time
ago i bet?

Whatever statement on my behalf here, it's very obvious that the mckinley
is going to have a superb future.







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