Author: Gabor Szots
Date: 10:21:05 11/01/05
Go up one level in this thread
On November 01, 2005 at 12:41:25, Aaron Gordon wrote: >>Thanks, Günther. A disappointment as P4 is concerned... >> >>Regards, >>Gábor > >As far as HT goes, please take Hyatts advice there. I don't know the exact >numbers, but here is a decent example. Lets say you've got a dual CPU system >where 1 cpu takes 60 seconds to hit 16 ply. As soon as you switch to 2 >threads/cpus, you get a 20% performance decrease. So, lets figure two cpus that >can do 16 ply in 60 seconds a piece, minus 20%. That puts us at ~36 seconds, a >nice improvement over 1 cpu. > >Now, with HT, it isn't a real second CPU. So, lets say we take that same >performance decrease and see what it does with HT enabled. >60 seconds per cpu again, 1 cpu. HT will probably benefit you about 10%, but, >going into SMP mode again drops you 20%. So, you actually lose performance. Now >your 60 second time turns into about 64.8 seconds (if I did my math properly, >heh). > >Here are some benchmarks I ran to compare a few systems. This is with Crafty >19.15 compiled by Bryan Hofmann (http://cito.atspace.com/) run with the "bench" >command and 48mb hash. I would have enabled HT for the P4 test, however, my P4 >does not have HT. > >3054kn/s - Athlon 64 2.85GHz (San Diego) 64 bit >2149kn/s - Athlon 64 2.85GHz (San Diego) 32 bit >1934kn/s - Athlon 64 1.80GHz (San Diego) 64 bit >1612kn/s - Athlon XP 2.50GHz (Barton) 32 bit >1350kn/s - Athlon 64 1.80GHz (San Diego) 32 bit >1209kn/s - Pentium 4 3.0GHz (Northwood) 32 bit >1095kn/s - Athlon XP 2500+ 1.83GHz (Barton) 32 bit Thanks, Aaron. The last line corresponds to my system. I got 1089 on my Barton.
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