Author: Slater Wold
Date: 10:04:01 12/09/03
Go up one level in this thread
On December 09, 2003 at 12:49:17, Robert Hyatt wrote: >On December 09, 2003 at 12:33:20, Slater Wold wrote: > >>On December 09, 2003 at 11:49:19, Mathieu Pagé wrote: >> >>>On December 09, 2003 at 11:16:02, stuart taylor wrote: >>> >>>>Is 2.2 Ghz. of a 64-bit computer a similar speed for chess as is 4.4 is it were >>>>a 32-bit one? >>>>If not, what? >>>>S.Taylor >>> >>>Hi! >>> >>>No, it is not. >>> >>>64-bit computer are not twice as fast as 32-bit ones. The number of bit >>>represent the natural lenght of an number on a cpu. Since chess engines use lot >>>of 64 bits numbers they will run faster on 64 bits machines because on 32-bit >>>machines they have to do some trick to do 64 bits maths that are natural on a 64 >>>bit cpu. >>> >>>I dont think the improvement will be in the range of 2x speed up. Anyway it will >>>vary from diffrents engines. >>> >>>Mathieu >> >>GCP reported 70% with Sjeng. >> >>Bob has reported about 50% with Crafty. > >Not exactly. I reported 1.0M with a 2.8ghz xeon, vs 1.6M with a 1.8ghz >opteron. If you factor in a clock speed equalization, the xeon slows to >1.8ghz and would produce about 650K nodes per second and the opteron would >be more than 2x faster. > >I have not done a direct comparison of 32 bit code vs 64 bit code on the >opteron as I have no 32 bit compiler available there. If I get to do that >at some point it time, it would be interesting. It would be more interesting >to be able to say "use only 32 bit ops, but use all 16 registers" to get a >_real_ feel for what 64 bits offers over 32 bits, but that looks even >harder to test. Well, we can always deduct. :) An opteron 144 (1.8Ghz) running SuSe and gcc33, using -m32 to produce 32 bit code, got these results on 186.crafty: 90.1 1109 The fastest 2.8Ghz Xeon on SPEC's website does: 92.0 1087 (2k AS IC++ 7.0 compiler) For all practical purposes, we can say that a O144 a P4 2.8Ghz Xeon are 'comparible'. 1.0M to 1.6M = 60% speedup
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