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Subject: Re: Fritz5 and memory

Author: Christophe Theron

Date: 11:52:42 05/29/98

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On May 29, 1998 at 06:04:42, Enrique Irazoqui wrote:

>On May 29, 1998 at 01:23:32, Christophe Theron wrote:
>
>>On May 28, 1998 at 20:01:08, Enrique Irazoqui wrote:
>>
>>>
>>>On a PII/300
>>>                100MB        50MB          25MB
>>>BS2830-14       208''        224''         301''
>>>BT2630-09       404''        406''         435''
>>>
>>>
>>>On a P200MMX
>>>                100MB        40MB          22MB
>>>BT2630-09       524''        560''
>>>Fritzmark       174          156           154
>>>
>>>Chessbase claim that by increasing hashtables from 40 MB to 100 MB on a
>>>P200MMX, Fritz 5 is 50 Elo points stronger. It doesn't make sense to me
>>>that doubling RAM has the same effect as doubling the processor speed.
>>>After the times above, maybe going from 25 to 100 MB hash Friz 5 can
>>>become some 20 points stronger.
>>>
>>>Enrique
>>
>>Thanks for the concrete data, Enrique.
>>
>>So we can see on these positions that Fritz gains 31% in speed on
>>BS2830-14, and 7% on BT2630-09 when we give it 4x times more hash
>>tables.
>>
>>Could you please post the positions in EPD format, so I will be able to
>>give the results for Tiger as promised?
>>
>>
>>    Christophe
>
>BS2830-14:
>r1bqr1k1/pp1n1ppp/5b2/4N1B1/3p3P/8/PPPQ1PP1/2K1RB1R w - - 0 0 bm Nxf7
>
>BT2630-09:
>r5k1/pp2p1bp/6p1/n1p1P3/2qP1NP1/2PQB3/P5PP/R4K2 b - - 0 0 bm g5
>
>It's true that many more positions are needed to make sure about the
>influence of hash size on Fritz 5, but I am too lazy to collect so much
>data. I picked 2 positions where F5 uses an amount of time typical of
>games at 40/2.
>
>Enrique

Tiger does not find the first position in a reasonnable time (it
evaluates Nxf7 as being slighty inferior as the moves it would play).

On the second position, the result is (computer is K5-100MHz):

With 0.5Mb hash table: g5 found in 127.10s
With   1Mb           :             114.52s (9.90% faster)
With   2Mb           :             108.36s (5.38% faster)
With   4Mb           :             101.06s (6.74% faster)
With   8Mb           :              96.77s (4.25% faster)
With  16Mb           :              91.50s (5.45% faster)
With  32Mb           :              88.37s (3.42% faster)


It is obvious that the table gets quickly filled when I give Tiger only
0.5Mb hash. I think it is getting full only at the end of the search
with 32Mb hash tables.

But it is hard to say by looking at the numbers that the search suddenly
slows down because of a full table.

The only thing that is obvious is that more hash brings less and less
speedup. There is always something to gain from more hash tables, but
not much when you already have, say, 16Mb.

This is true for Tiger, and one could object that Fritz behaves
differently, which still has to be shown.

If Fritz gets the same percentage speedup when you double its hash
tables than other programs, and that's what I believe, then it is not
clear to me why Fritz is considered as an exception regarding hash table
management and needs...

How is it that we hear so much about Fritz5 and nothing about, say,
Virtual Chess, which is an underestimated great program? Should I
remember you which is the current world champion amongst the
professional microcomputer programs?


    Christophe



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