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News AMD shows off 3rd Gen AMD Ryzen CPUs featuring Zen 2 cores

Discussion in 'Article Discussion' started by bit-tech, 9 Jan 2019.

  1. MLyons

    MLyons Half dev, Half doge. Staff Administrator Super Moderator Moderator

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    Some boards are also buggy such as I believe MSI had a buggy BIOS recently that was inflating power consumption.
     
  2. edzieba

    edzieba Virtual Realist

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    Then there's the power envelope shaping: If AMD were being extra cheeky, they could be listing the PL1 (long term) performance level and the PL2 (short term) maximum power level. Power envelope changes predominantly affect all-core utilisation rather than single-core, so Cinebench would be affected far more than e.g. gaming. Motherboards with varying power draws are nothing to do with components on the board itself, but instead how they use (or rather abuse) the power envelope shaping. For example setting Tau (PL2 duration) to some effectively infinite number so the processor never drops to PL1, or setting PL1 to equal PL2.
     
  3. perplekks45

    perplekks45 LIKE AN ANIMAL!

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    AMD posted peak usage per system in the Cinebench run: 191W for Intel and 134W for AMD. That is system power draw. Given that RAM, SSD and GPU are the same, the interesting factors for power draw are CPU and mainboard. We know they used a Gigabyte Z390 Aorus board for the Intel system. For AMD it just states "Generic AMD mainboard" or some-such. Question marks remain.

    The definition of TDP was discussed widely and wildly at the end of 2018. Honestly, right now it's a mess.
     
  4. edzieba

    edzieba Virtual Realist

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    The simple answer is there is no single useful number you can point to as "TDP", and there hasn't been since turbo modes became a thing a decade ago. It persists like the useless technique of describing monitors by their diagonal - which tells you practically nothing about the actual size and shape of the panel because we stopped using 4:3 as a universal standard ~15-20 years ago - because any actually useful measure requires learning how power envelopes work and supplying more than one value. Same issue as the More Megapixels is More Better issues that digital cameras encountered, or the More Cores is More Better we have today.
     
  5. perplekks45

    perplekks45 LIKE AN ANIMAL!

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    They could just say peak power usage. Or release a small table with max boost clocks for X cores and corresponding peak power usage. Yes, more complex, but actually useful. And I don't care about the majority, we are their target group, aren't we? We understand that stuff, because we invest the time.
     
  6. edzieba

    edzieba Virtual Realist

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    Not really. Peak power is peak power, and with modern power management can be almost arbitrarily high with fine-grated thermal sensing allowing segments of a chip to edge extremely close to breakdown voltages and currents on-the-fly depending on available thermal headroom, on a millisecond-to-millisecond timescale or smaller. If you then decide "OK, rating an instantaneous power of several hundred watts is clearly silly, so we'll use a sliding average window" you then are right back to the situation today where you need to decide the size of that window.
    The target group for TDP specs are the OEMs implementing custom thermal solutions. The most even an enthusiast consumer is going to do is picking someone else's thermal solution to purchase.
     
  7. perplekks45

    perplekks45 LIKE AN ANIMAL!

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    All fair points, but what else can we ask Intel/AMD to do about that mess? I mean, the 9900K has a TDP of 95W, a recommended thermal solution of 130W, and easily pulls 150W+.
     
  8. Anfield

    Anfield Well-Known Member

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    Just pick a piece of Software that is demanding (lets say for example the Corona benchmark), measure power consumption while thats running and use that as the advertised power consumption.
     
  9. perplekks45

    perplekks45 LIKE AN ANIMAL!

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    Which would (highly likely) bring us back to peak power consumption. ;)
     
  10. edzieba

    edzieba Virtual Realist

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    Or it'd do what we get today, further up this very thread: drop down to the sustained power, then have people complain that it doesn't reflect peak power.
     
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