Author: Slater Wold
Date: 11:59:57 12/09/03
Go up one level in this thread
On December 09, 2003 at 13:48:49, Eugene Nalimov wrote: >On December 09, 2003 at 13:30:11, Slater Wold wrote: > >>On December 09, 2003 at 13:17:55, Robert Hyatt wrote: >> >>>On December 09, 2003 at 13:04:01, Slater Wold wrote: >>> >>>>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: >>> >>>We can't compare with that at all. That is a _way_ old version, obviously. >>> >>>I can't do -m32 on this machine, as the libraries are all -m64 and they >>>become incompatible (I have already tried this a few days back in fact.) >>> >>> >>>> >>>>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'. >>> >>>OK. Can't argue there with no data of my own to rely on.. >>> >>> >>> >>>> >>>>1.0M to 1.6M = 60% speedup >>> >>>Not directly attributable to 64 bit however. -m32 restricts you to 8 >>>registers, while -m64 adds the other 8. That also factors in and makes >>>this less clear. >> >>Like I said, it was just a 'deduction'. I know you're pretty scientific, but >>this was just a rough comparison. >> >>I'd be confident in this statement however: "64-bits, depending on application, >>can speedup a typical chess program from 40% to 70%." >> >>Which is nice, considering it is practically 'free'. > >I am not so sure. > >Please take a look at one of the recent Opteron SPEC admissions: >http://www.spec.org/cpu2000/results/res2003q4/cpu2000-20030922-02519.html. > >3 out of 12 programs (1/4 of all programs) were compiled with "-m32" flag, >because they are faster in 32-bit mode. > >Thanks, >Eugene Well..I am getting an AMD system in the next week or so. I just haven't decided on what config. Why don't you hook me up with AMD64 Windows, and compiler. Then I can give you more 'for sure' and a lot less 'maybe'. :)
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