Author: William Penn
Date: 05:08:26 08/29/03
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On August 28, 2003 at 23:13:19, Derek Paquette wrote: >On August 28, 2003 at 15:39:19, William Penn wrote: > >>Are these Shreddermarks normal? >> >>AMD Athlon XP 2400+ processor, 2.0 GHz, 640MB installed, 608MB available, >>Windows XP Home, Shredder 7 >> >> 4MB hash, Shreddermark=1591, 391kN/s >> 64MB hash, Shreddermark=1392, 349kN/s >>128MB hash, Shreddermark=1113, 291kN/s >>256MB hash, Shreddermark= 856, 222kN/s >>384MB hash, Shreddermark= 655, 179kN/s >>432MB hash, Shreddermark= 618, 165kN/s >>455MB hash, Shreddermark= 618, 161kN/s (maximum hash) >> >>I don't understand why the Shreddermark and kN/s decreases as the amount of hash >>is increased. That's what concerns me. >> >>I presume that the more hash allocated then the faster the engine is supposed to >>calculate. If so, then why does the speed decrease with more hash? >>WP > >the reason is you are getting close to your maximum limit, i have 256 mb of ram, >if i run my chess program at 128, its fine, using shredder, if i use 192, it >slows down, and I mean really slows down, from 300 kn/sec to about 45 kn/sec > >if you had 1 GB of ram, you wouldn't even notice a diff. But... 256MB hash isn't near my maximum limit, yet it cuts the kN/s speed almost in half (compared to 4MB hash) as indicated by the Shreddermark operation. I do NOT see these kinds of slowdowns when I'm analyzing ordinary chess positions in infinite analysis mode. So there appears to be some kind of peculiarity of the "Shreddermark" operation. The results certainly appear to be misleading. I now realize the reason is probably that it takes awhile for the hash table to be setup in virtual memory. The more hash, the longer that takes. It can take several minutes on a system that's low on installed memory, and then you'll notice the hard drive chugging away constantly in that case. Even with a lot of memory to spare, it can still take awhile - perhaps a few seconds - depending on the speed of the op system, hard drive, memory, etc. But the Shreddermarks are probably run very quickly, in a split second, not giving any time for that to happen. If I've evaluated this correctly then, the Shreddermarks (or Fritzmarks etc) are NOT a reliable indication of ... of ... "what"? Basically, they just don't seem to be a very reliable indicator, for my purposes at least. I only use Shredder 7 in infinite analysis mode at very long time controls, usually at least 1 hour per move, sometimes 24 hours per move. WP
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