Power Consumption and Frequency Ramps

On the box, both processors are listed as having 65 W TDPs. With its Zen-based hardware, AMD has been relatively good at staying around that official on-the-box value, even during turbo. In the last generation, AMD introduced a feature called PPT, or Package Power Tracking.

  1. For 105 W processors, PPT is >142 W
  2. For 65 W processors, PPT is >88 W
  3. For 45 W processors, PPT is >60W

This allows the processor to raise its power limits, assuming it isn’t breaching thermal limits or current limits, and consequently raise the frequency. As a result, while we see 65 W on the box, the real world power consumption during most tasks is likely to be nearer 88 W, unless the current or thermal lines are crossed.

As a new element to our testing, we are recording power over a number of benchmarks in our suite, rather than just a simple peak power test.

AMD Ryzen 3 3300X

For the faster chip, we saw a peak power in both of our tests of around 80 W.

With yCruncher, which is somewhat of a periodic load, the power consumption dropped over time to nearer 75 W.

3DPM is more obvious with its idle steps between loads, being 10 seconds on then 10 seconds waiting. The power almost peaked at a similar amount here.

In both of these graphs, the package power when idle is around 16-17 W. I looked back through the data, and noticed that out of this power only 0.3 W was actually dedicated to cores, with the rest being towards the big IO die, the memory controllers, and the Infinity Fabric. That’s still pretty substantial for an idle load.

At low loads, the power per core was around 14 W, while at full load it was slightly less depending on the test. This is a bit away from the 20 W per core we get from the high end Zen 2 processors, but these only go to 4.3 GHz, not 4.7 GHz+. This is about in line with what we expect.

On our frequency ramp test, the Ryzen 3300X went from an idle state to peak power within 17 milliseconds, or approximately a frame at 60 Hz.

One of the new features with Ryzen 3000 is CPPC2 support, which AMD claims to reduce idle-to-turbo ramping from 30 milliseconds to 2 milliseconds. We’re seeing something in the middle of that, despite having all the updates applied. That being said, the jump up to the peak frequency (we measured 4350 MHz, +50 MHz over the turbo on the box) is effectively immediate with zero skew across a range of frequencies.

AMD Ryzen 3 3100

Given that the TDP number on the side of the box says 65 W as well, any reasonable user would assume that the power of this chip would be equal, right? Regular readers will know that this isn’t always the case.

In our yCruncher test, because the turbo frequency is lower than the 3300X, it means the voltage can be lower, and thus power is lower. Our history of testing Zen 2 has shown that these cores get very efficient at lower frequencies, to the point where our processor doesn’t even break that 65 W threshold during yCruncher.

Similarly the 3DPM peaks are also lower, barely going to 55 W during an AVX2 workload.

On the frequency ramp side, we see another instance of a 16-17 ms transition.

Summary

For the peak power out of all of our testing, we saw the Ryzen 3 3300X hit a maximum of 80 W, and the Ryzen 3 3100 go to 62 W. When we compare that to the Core i7-7700K, at 91 W TDP / 95 W peak, combined with most of the results on the next few pages, AMD by comparison is more efficient.

AMD Ryzen 3 3300X and 3100 Review Test Bed and Setup
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  • PeterCollier - Saturday, May 9, 2020 - link

    Where are the AMD APUs?
  • PeterCollier - Friday, May 8, 2020 - link

    0
  • The_Assimilator - Thursday, May 7, 2020 - link

    Please shut up.
  • b0rnslippy - Thursday, May 7, 2020 - link

    Why? not all of them are blind Ian supporters. Just saying it like we seeing it.
  • Teckk - Thursday, May 7, 2020 - link

    You think this article is biased towards Intel?
  • mrvco - Friday, May 8, 2020 - link

    The narrative seems forced in lieue of current and price competitive offerings from Intel. Hard to blame AT though, must publish. Regardless, AMD is absolutely ballin'.
  • brunis.dk - Saturday, May 9, 2020 - link

    Unbelievable.. this chip is a quarter of the price and is a fucking steel and totally embarrasses Intel's best .. and he thinks its Intel biased, what the actual F?
  • Spunjji - Monday, May 11, 2020 - link

    Yeah, this "logic" isn't working out at all.

    I'm hard pressed to tell whether these comments are from actual dyed-in-the-wool AMD fanboys or a few Intel nuggets doing their best impersonations of how they think one would behave. 🤔
  • PeterCollier - Monday, May 11, 2020 - link

    Socrates said it's the mark of an informed mind to entertain a thought without rejecting it.

    It's the mark of an uninformed mind to be unable to entertain an opposing viewpoint and instead dismiss it as trolling.
  • FreckledTrout - Monday, May 11, 2020 - link

    Those trolls in 400BC were a pain writting stuff in stone and all.

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