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AMD FX-8350 Linux Performance-Per-Watt

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  • phoronix
    started a topic AMD FX-8350 Linux Performance-Per-Watt

    AMD FX-8350 Linux Performance-Per-Watt

    Phoronix: AMD FX-8350 Linux Performance-Per-Watt

    The latest Phoronix benchmarks to share of the AMD FX-8350 "Vishera" processor are performance-per-Watt results for the Piledriver eight-core processor compared to the previous-generation Bulldozer FX-8150. Tests were conducted when running at stock speeds as well as overclocked settings.

    http://www.phoronix.com/vr.php?view=18074

  • devius
    replied
    Originally posted by xception View Post
    I'm sorry but the performance per watt graphs are wrong
    No need to apologize, since you are correct as most of the posts in this thread confirm. The one who should be giving an explanation is Michael, but I don't even know if he realizes the formulas he used to calculate performance per watt are wrong.

    Originally posted by xception View Post
    Numbers
    - green took 31.45 seconds @ 220 Watts
    - blue took 33.03 seconds @ 262 Watts
    So in performance per watt, green is the obvious winner - less time to finish, less average power.
    That's pretty obvious. It's not like Phoronix has a ton of credibility anyway so no real harm done.

    Leave a comment:


  • xception
    replied
    I'm sorry but the performance per watt graphs are wrong, that is assuming the power consumption graphs are correct, for example in the C-Ray test the blue line is both higher and longer than the green line, so the system in blue (AMD FX-8150 @ 4.00 Ghz) took more power at each moment in time and also took more time to complete the test than the system in green (AMD FX-8350) - yet the performance per watt says that more is better and green is lower than blue (which from the other graph should green should have more) ... so either less is better in the performance per watt graphs or the formula used for the calculation is wrong.

    Numbers
    - green took 31.45 seconds @ 220 Watts
    - blue took 33.03 seconds @ 262 Watts
    So in performance per watt, green is the obvious winner - less time to finish, less average power.
    Last edited by xception; 10-28-2012, 06:33 AM.

    Leave a comment:


  • curaga
    replied
    Originally posted by bug77 View Post
    Would it be the first time power saving on Linux didn't work right?
    It could just as well be 8150 power-saving not working well on Windows. Don't jump to conclusions.

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  • bug77
    replied
    Originally posted by curaga View Post
    Hm, right. There's still the discrepancy of the idle and load numbers though (at stock), in Win reviews 8350 was lower in both, here the other way around.
    Would it be the first time power saving on Linux didn't work right?

    Leave a comment:


  • curaga
    replied
    Hm, right. There's still the discrepancy of the idle and load numbers though (at stock), in Win reviews 8350 was lower in both, here the other way around.

    Leave a comment:


  • oleid
    replied
    @Michael:
    Reading the article, every test result my brain stretched and wondered what was wrong. Yet, as mcgreg already said, the only really valid number to compare the processors' efficiency is to calculate the energy which is needed to get the job done. And this, Michael, should be sone by calculating the integral of your W(t) curves... As you have discrete measurements with a fixed step size in time, dt, it's nothing more than a sum over all measurements, multiplied by dt.

    dt * \sum_{i=0}^{N} W_i

    If you know how many floating point operations this task needs, you can calculate the energy per floating point operation -- which is the same as the average number of Watts per Speed (measured in flop / sec).

    Leave a comment:


  • mcgreg
    replied
    Meh, is there anything I calculated correctly?

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  • abacaba
    replied
    Originally posted by mcgreg View Post
    also I'd calculate
    297,8 * 79,25 = 23601 kJ for the fx 8150 @ 4,6ghz
    264,3 * 72,98 = 19288 kJ for the fx 8350 @ 4,6 ghz

    mcgreg
    Correct, except "J", not "kJ".

    Or, one can get inverse: 1/23601 = 0.000042371, which means ~42 microlinuxkernels (are compiled) per joule. Here, the more the number is the better.

    Leave a comment:


  • mcgreg
    replied
    Ahh yes, I used the wrong numbers, and you corrected it, thx.

    So, the results is clear: the FX 8350 is more efficient in performance / watt and michaels results is wrong then - this is actually what most people were already thinking, we just proved it.

    Leave a comment:

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