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Main
Date: 26 Nov 2005 02:57:39
From: Michael951
Subject: Deep Shredder not twice as fast?
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Hello!
I have Shredder, and recently I upgraded to DeepShredder because I hav
a dual processor 3.5 MHZ (4 gigs of RAM). However, I noticed that i
only runs about 20% faster than the single processor. For example, in
typical middlegame, the single processor version may run 450kn p/s
whereas the dual (same exact position) would run about 550. Is thi
normal or am I doing something wrong? Also I have the hash at 512mgs
should I double that for this system (even though increasing the has
amount slows down the computational speed)?
Thanks in advance for your suggestions!
Michae
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Michael951
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Date: 27 Nov 2005 10:41:21
From: MorphyFischer
Subject: Re: Deep Shredder not twice as fast?
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Michael,
Parallel processing gains are not a linear function of the number of
processors. That is because deciding which processor gets which subset
of the tree, then synchronizing all of the tree-sharing information,
can require a good % of one of the processors.
You experience better gains with more and more processors, roughly
equal to the squae root of the number of processors.
For 4 processors, you would be twice as fast.
For 16 processors, 4 times as fast.
For 2 processors, you would expect a maximum gain of 40% (square root
of 2.)
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Date: 26 Nov 2005 15:21:27
From: Nanga Parbat
Subject: Re: Deep Shredder not twice as fast?
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Michael951 wrote:
> Hello!
> I have Shredder, and recently I upgraded to DeepShredder because I have
> a dual processor 3.5 MHZ (4 gigs of RAM). However, I noticed that it
> only runs about 20% faster than the single processor. For example, in a
> typical middlegame, the single processor version may run 450kn p/s,
> whereas the dual (same exact position) would run about 550. Is this
> normal or am I doing something wrong? Also I have the hash at 512mgs,
> should I double that for this system (even though increasing the hash
> amount slows down the computational speed)?
> Thanks in advance for your suggestions!
> Michael
Could be an Intel issue. On my AMD64X2 @ 2400MHz it seldom drops below
1000kn. I still use Shredder7. ( Shreddermarks +- 3750)
Nanga
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