Author: Vincent Diepeveen
Date: 00:04:11 07/15/01
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On July 14, 2001 at 09:07:15, Werner Schuele wrote: >Hi, >from featchers txt for pocketcrafty I read that pocketcrafty reaches about 5000 >- 10000 nps on ipaq 206 mhz. On my PC with 650 MHz crafty reaches around 300k >nps. When I reduce speed to 200MHz on the start position I can see 80 000 nps. >Where comes this difference (10 times more)? >Werner Crafty is designed for a 64 bits environment, not for a 32 bits processor. x86 processors don't look that bad as there are instructions like BSF and BSR at the processor, which are crucial bitboard instructions. If you take away those advantages then crafty has to rely on slow array lookups. I do not know which processor is in the compaq ipaq, but most likely also the number of instructions a clock it can put through is very small. For some programs that is no problem, as in todays processors a lot of instructions block a good instruction a clock ratio, but imagine that theoretical a RISC processor is doing 1 instruction a clock. Pentiumpro was a major improvement here (of course forgetting great processors such as alpha 21264) as it could do 3 instructions a clock, practical i do notknow what is normal, but definitely something around 2 instructions a clock for crafty would seem normal. I can imagine that at a pocket processor this is not even near 2 instructions a clock but more like 1 instruction a clock. That is a factor 2 loss in speed.
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