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

  1. #11
    Join Date
    May 2014
    Location
    Germany
    Posts
    98

    Default Wrong, wrong, wrong

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

  2. #12
    Join Date
    Sep 2007
    Posts
    329

    Default

    Quote 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.

  3. #13
    Join Date
    Aug 2014
    Location
    Buenos Aires, Argentina
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    2

    Default

    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.

  4. #14
    Join Date
    Oct 2012
    Location
    Washington State
    Posts
    488

    Default

    Run all these tests configured with LLVM-Clang 3.5.

  5. #15
    Join Date
    Oct 2007
    Location
    Toronto-ish
    Posts
    7,514

    Default

    Quote 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; 08-14-2014 at 01:49 AM.

  6. #16
    Join Date
    Jul 2012
    Posts
    4

    Default

    Quote 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

  7. #17
    Join Date
    Dec 2011
    Posts
    16

    Default

    Quote 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.

  8. #18
    Join Date
    Oct 2009
    Posts
    2,122

    Default

    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.

    http://www.torontohydro.com/sites/el.../tourates.aspx

  9. #19
    Join Date
    Jan 2014
    Location
    Tallahassee, FL 32304
    Posts
    114

    Default

    Quote Originally Posted by droidhacker View Post
    What is the point of torontohydro link? It smells more of an advertisement to me.

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