Author: Ed Schröder
Date: 22:05:15 07/06/99
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On July 06, 1999 at 17:01:02, Alain Lyrette wrote: > >On July 06, 1999 at 14:57:58, James T. Walker wrote: > >>Hello, >>Does anyone know if there is any advantage to using the K6-3 over the K6-2 at >>the same Processor speed(450Mhz) for chess programs?? >>Jim Walker > The only >difference between k6-2 and k6-3 is that there is 256kb of L2 cache on the die >itself of the k6-3 and that cache is running at the same speed of the cpu NOT >the speed of the bus(100 mhz).What used to be called L2 cache is now L3 cache.As >mentionned before knowledge based programs (Rebel,Hiarcs) are relying much more >on cache than fast searchers like Fritz and Nimzo.About 2 weeks ago someone >posted here something like saying that csst2 was almost twice as fast on a >pentium than on k6....which is very surprising to me.... It is surprising yes. Its reason: Programs like CSTAL and Rebel and probably Hiarcs too have a large evaluation function. The disadvantage of a large evaluation function is that it uses many so called varaibales (=memory). Using memory is very expensive in terms of speed. That's why chip developers invented: a) first level cache (super fast memory) b) second level cache (fast memory) to speed up all memory requests from programs. For years second level cache runs at 66 Mhz and recently this was increased to 100 Mhz. The AMD-K6-III is a breakthrough because the second level cache runs at full processor speed. If you have (say) a 450 Mhz K6-III the second level cache will run at 450 Mhz too instead of the old 100 Mhz. Now to chess programs and its effects, chess programs with small evaluation functions will hardly profit from this new technique. Chess programs with a big evaluation function will profit a lot. Rebel's speed-up is about 100%. CST speed up is 125% which is no surprise for me becuase CST has the largest eval of all. Ed Schroder
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