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Boyd Stephen Smith Jr. wrote: |
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> On Wednesday 31 January 2007 09:58, Alan McKinnon |
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> <alan@××××××××××××××××.za> wrote about 'Re: [gentoo-user] |
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> Symlinking /usr/portage/distfiles': |
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>> On Wednesday 31 January 2007, Bo Ørsted Andresen wrote: |
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>>> Furthermore Pentium 4 is a joke (it performs horribly). A 2 GHz |
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>>> (Dothan I presume) Pentium-M should be faster than a 2,8 GHz Pentium |
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>>> 4. My timing is for an 1,6 GHz (Banias) Pentium-M btw. |
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>> This sounds odd, but I'm not a cpu expert so can't really comment. Care |
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>> to elaborate on why the P4 performs so horribly? |
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> |
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> The instruction pipeline is very long, the CPU <-> RAM bandwith is quite |
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> small, and the pipeline has to be emptied any time the branch predictor is |
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> wrong. While the pipeline fills, the CPU works but no results are |
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> visible. |
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> |
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> Hz has never been a complete trump of other issues affecting CPU |
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> performance, but is always a factor to consider. (Among CPUs that are |
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> otherwise identical, higher Hz wins.) |
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> |
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Also Pentium-M has a lower latency L2 cache than P-4. With respect to |
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pipeline lengths I was curious to see what they actually were: P-4 has |
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20 stages, P-M has.. err... < 20 stages (Intel won't say exactly!). |
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I found this an interesting read for those of you interested in this: |
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http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=2342&p=1 |
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Cheers |
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|
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Mark |
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-- |
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