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Trying The Configurable 45 Watt TDP With AMD's A10-7800 / A6-7400K

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  • #11
    Wrong, wrong, wrong

    "Xonotic was also more power efficient with the stock TDP."
    The chart above schows clearly the opposite!

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    • #12
      Originally posted by drSeehas View Post
      "Xonotic was also more power efficient with the stock TDP."
      The chart above schows clearly the opposite!
      Yep, and furthermore, the provided values show, that the effiency graphs of the last page are wrong.

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      • #13
        When the test is more is better, the results of performance per watt are fine.
        When the test is lower is better, the results are wrong.

        Examples with 1 variable and 1 constant:

        More is better test:

        PC 1 : 100 frames per second / 50 watt = 2
        PC 2 : 100 frames per second / 25 watt = 4
        Correct.

        PC 1 : 100 frames per second / 50 watt = 2
        PC 2 : 50 frames per second / 50 watt = 1
        Correct.


        Less is better test:

        Seconds/Watt(wrong)

        PC 1 : 100 seconds / 50 watt = 2
        PC 2 : 100 seconds / 25 watt = 4
        Correct.

        PC 1 : 100 seconds / 50 watt = 2
        PC 2 : 50 seconds / 50 watt = 1
        Incorrect.


        Watt/Seconds(wrong)

        PC 1 : 50 watt / 100 seconds = 0.5
        PC 2 : 25 watt / 100 seconds = 0.25
        Incorrect.

        PC 1 : 50 watt / 100 seconds = 0.5
        PC 2 : 50 watt / 50 seconds = 1
        Correct.



        The right formula is:

        1 / ( Seconds * Watt) and normalize.

        PC 1 : 1 / (50 watt * 100 seconds) = 0.0002
        PC 2 : 1 / (25 watt * 100 seconds) = 0.0004
        Correct.

        PC 1 : 1 / (50 watt * 100 seconds) = 0.0002
        PC 2 : 1 / (50 watt * 50 seconds) = 0.0004
        Correct.

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        • #14
          Run all these tests configured with LLVM-Clang 3.5.

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          • #15
            Originally posted by smitty3268 View Post
            Yeah, i remember that and thinking "how the hell does michael think this makes any sense at all"?
            Things make more sense when you wrote them. I have to wait for a while between writing and proof reading if I want to have a chance of finding all the stupids. Today I was reading through an analysis I wrote a few months ago and it was glaringly obvious that I had missed something important. At the time... everything looked fine.

            AFAIK the reason newspapers & magazines have editors is not so much that writers can't write, but that writers can't find problems in articles *they* wrote while the writing is still fresh in their heads... so you either need to slow things way down or use a different head for review. That's why even a quick & dirty peer review works so well.
            Last edited by bridgman; 14 August 2014, 01:49 AM.
            Test signature

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            • #16
              Originally posted by moony View Post
              So for one task (compiling the kernel), the 45W TDP setting uses less watts per hour, therefore it's more efficient!
              The reason is, the stock voltage settings are far from optimal. If undervolting AMD CPUs, power efficiency simply skyrockets.
              Also, they did something with voltage settings and power management in A10-7800 - it's performance per watt is really nice, compared to 7850k

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              • #17
                Originally posted by bridgman View Post
                Things make more sense when you wrote them.
                Actually I just found an error in my own post:

                < the 45W TDP setting uses less watts per hour
                > the 45W TDP setting uses less watt-hours
                :-)

                The intention was to explain, that the 45W TDP setting uses less watt-hours, to complete the same task.

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                • #18
                  More useless observations.....

                  The objective here isn't to improve efficiency while pegging the CPU. The objective here is to reduce overall system power consumption. And while you may initially believe that it makes more sense to buy a slower CPU to begin with, that isn't always the case. For example, when you have an office full of dozens of machines running **office software**, subject to different ENERGY RATES based on time of day, ultimately, you want to be able to reduce the *average* system power consumption during peak times.

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                  • #19
                    What is the point of torontohydro link? It smells more of an advertisement to me.

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