Author: James T. Walker
Date: 18:08:06 10/22/98
Go up one level in this thread
On October 22, 1998 at 09:00:23, Kai Skibbe wrote: >On October 22, 1998 at 08:17:59, Robert Hyatt wrote: > >>On October 22, 1998 at 01:12:46, Kai Skibbe wrote: >> >>>On October 21, 1998 at 11:08:15, James Robertson wrote: >>> >>>>On October 21, 1998 at 10:54:16, James T. Walker wrote: >>>> >>>>>If I understood a previous thread, Dr. Hyatt indicated that there is >effectively >>>>>no move ordering done by most programs(At least Crafty)? >>>> >>>>Crafty orderes moves by firstly trying the hash move, then killers? (I'm not >>>>sure), then gainful captures, etc. There is actually a lot of move ordering >>>>done, but for Crafty, it is all in *generating* more promising moves first. My >>>>program has very primitive move ordering, using only pv search, gainful >>>>captures, and killer moves. Each one of these heuristics has reduced move time >>>>by 25% to 50%, so obviously move ordering is really important. I plan to add >>>>hash, history (this will profoundly rearrange your move list), and other stuff >>>>as soon as I find out I failed biology, and say "the heck with it. Might as well >>>>work on my program!" :) >>>> >>>>>Can anyone please >>>>>answer this for me?? It seems unreal that there would be no attempt to order >>>>>the moves so that the most promising moves were searched first. >>>>> >>>>>Another question-- Can anyone tell me if there is any advantage to having 1 meg >>>>>of L2 cache vs 512K relative to chess programs? >>> >>>Hi Jim, >>> >>>the speed difference will be minimal, but with most motherboards the cacheable >>>area with 1MB L2Cache is twice as with 512KCache. So I think 1M L2 Cache is >>>worth the extra money. >>>For example I have the NMC 5VMMX with 1MB Cache and the cacheable area is 256MB >>>RAM. With only 512KB Cache the cacheable area would be only 128MB RAM. >>> >>> >>>Best Regards >>>Kai >>> >> >> >> >> >> >> >> >> >> >> >>This isn't always true. IE the PII's (anything 300mhz and up at least) >>can cache the full 32 gigs of main memory, if you can afford it. The >>size of cache should have no effect on how much memory can be cached. It >>depends on the design of the cache and the size of the tag ram used for >>verifying cache hits. >> >>However, I haven't seen any designs where doubling cache doubles the amount >>of cacheable RAM... because the size of the cache is usually a jumper on >>motherboards. There were some few pentiums and pentium II's that could >>only cache the first 64MB... but for any pentium II, external cache >>doesn't exist, so we are talking about regular pentiums or clones I assume, >>since the pro's and II's have the L2 cache internal... > >Hi Bob, > >I think you are right with intel pentium II chips. But my motherboard has a >Socket 7 and the available processors for this socket doesn´t have the L2-cache >inside. With 1MB L2-Cache my motherboard has a chacheable area of 256MB RAM. You >can´t change the tag ram to increase the cacheable area. >I think that doubling the cache size has the same affect of doubling the >cacheable area to all motherboard with the VIA-chipset. Other none >Intel-chipsets may have the same affect. >Another influence of the cacheable area is the cache strategy. I think with >"write back" the cacheable area is half (128MB) as with "write through" (256MB). > > >Best regards >Kai Thanks for the info. I thought I read somewhere that the 486 had like 16k of L1 cache(On the Chip) and later the Pentiums came with 32K of L1 cache. I thought the L2 cache was just an extension of the L1 only on the motherboard instead of inside the chip. I had no idea how it covers the main memory size wise but had also heard of what you said about certain cache size covering certain amount of main memory. I just don't know how this affects the speed of chess programs. I am considering a new computer and wavering between a K6-2 with 1 meg L2 versus a Pentium II with 512K of L2. Again thanks for the info. Jim Walker > > >> >>> >>>> >>>>I haven't a clue! >>>> >>>>>Thanks,\ >>>>>Jim Walker >>>> >>>>Hope I helped, >>>>James
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.