The AMD 2nd Gen Ryzen Deep Dive: The 2700X, 2700, 2600X, and 2600 Tested
by Ian Cutress on April 19, 2018 9:00 AM ESTPrecision Boost 2 and XFR2: Ensuring It Hertz More
One of the biggest changes for the new Ryzen-2000 series is in how the processor implements its turbo. Up until this point (except the recent APU launch), processors have relied on a step function implementation: the system determines how many threads are loaded, attempts to implement a specific frequency on those cores if possible, and then follows the look-up table relating thread count to frequency. AMD’s goal in Precision Boost 2 is to make this process more dynamic.
This image from AMD is how the feature is being represented: the system will determine how much of the power budget is still available, and turbo as much as possible until it hits one of the limiting factors. These factors can be any of, but not limited to, the following:
- Total chip peak power
- Individual core voltage/frequency response
- Thermal interactions between neighboring cores
- Power delivery limitations to individual cores/groups of cores
- Overall thermal performance
AMD’s new Ryzen Master 1.3 software, when used on a Ryzen 2000-series processor, has several indicators to determine what the limiting factors are. For the most part, the way the processor will boost and respond to the environment, will be transparent to the user.
The best way to test this in action, from my perspective, is to look at the power draw of the first generation and second generation Ryzen processors. We can examine the internal estimated power consumption of each core individually as thankfully AMD has left these registers exposed, to give the following data:
This is only the core consumption power, not the package power, which would include the DRAM controller, the Infinity Fabric, and the processor IO. This means we get numbers different to the rated TDP, but the danger here is that because the Ryzen 7 2700X has a 10W TDP higher than the Ryzen 7 1800X, where the 2700X draws more power it could seem as if that is the TDP response.
Just plotting the power consumption gives this graph:
Even in this case it is clear that the Ryzen 7 2700X is drawing more power, up to 20W more, for a variable threaded load. If we change the graph to be a function of peak power:
The results are not quite as clear: it would seem that the 1800X draws, as a percentage of peak power, more at low thread count, but the 2700X draws more at a middling thread count.
It is worth noting that the end result of Precision Boost 2 is two-fold: more performance, but also more power consumption. Users looking to place one of the lower powered processors into a small form factor system might look at disabling this feature and returning to a standard step-function response in order to keep the thermal capabilities in check.
A side note – despite the marketing name being called ‘Precision Boost 2’, the internal BIOS name is called ‘Core Performance Boost’. It sounds similar to Multi-Core Enhancement, which is a feature on some Intel motherboards designed to go above and beyond the turbo mechanism. However, this is just AMD’s standard PB2: disabling it will disable PB2. Initially we turned it off, thinking it was a motherboard manufacturer tool, only to throw away some testing because there is this odd disconnect between AMD’s engineers and AMD’s marketing.
Extended Frequency Range 2 (XFR2)
For the Ryzen 2000-series, AMD has changed what XFR does. In the previous generation it was applied on certain processors to allow them to boost above the maximum turbo frequency when the thermal situation was conducive to higher frequencies and higher voltage in low thread-count states. For this generation, it still relates to thermals, however the definition is applied to any core loading: if the CPU is under 60ºC, the processor can boost no matter what the loading is above its Precision Boost 2 frequency (so why not get a better PB2 implementation?). The core still has to be within a suitable voltage/frequency window to retain stability, however.
On certain motherboards, like the ASUS Crosshair VII Hero, there are additional options to assist XFR2 beyond AMD’s implementation. ASUS does not go into specific details, however I suspect it implements a more aggressive version, perhaps extending the voltage/frequency curve, raising the power limits, and/or adjusting the thermal limit.
Facebook
Twitter
RSS
545 Comments
View All Comments
Maxiking - Tuesday, April 24, 2018 - link
"I just finished running Rise of the Tomb Raider benchmarks, 1080p, very high preset, FXAA.Unpatched:
Mountain Peak: 131.48 FPS (min: 81.19 max: 197.02)
Syria: 101.99 FPS (min: 62.73, max: 122.24)
Geothermal Valley: 98.93 FPS (min:76.48, max: 117.00)
Overall score: 111.31 FPS
Windows patch only:
Mountain Peak: 135.34 FPS (min: 38.21 max: 212.84)
Syria: 102.54 FPS (min: 44.22, max: 144.03)
Geothermal Valley: 96.36 FPS (min:41.35, max: 148.46)
Overall score: 111.93 FPS
Windows patch and BIOS update:
Mountain Peak: 134.01 FPS (min: 59.91 max: 216.16)
Syria: 101.68 FPS (min: 38.95, max: 143.44)
Geothermal Valley: 97.55 FPS (min:46.18, max: 143.97)
Overall score: 111.62 FPS
Average framerates don't seem affected."
From the link you posted, you got rekt by yourself.
Ranger1065 - Wednesday, April 25, 2018 - link
Nicely done Mr Aardvark. That made me smile.mikael.skytter - Tuesday, April 24, 2018 - link
Thanks for a great review. Any chance it would be possible to look into how SpeedShift 2 compares to AMD:s solution for short burst loads and clock ramp-up?Thanks!
koekkoe - Tuesday, April 24, 2018 - link
My favorite part in the article: fsfasd.Meow.au - Tuesday, April 24, 2018 - link
I’ve visited the comments section a few times since the publication. As a psychologist in training, I’ve found it interesting as the initial complaints about this review were reasonable (it doesn’t match other sites), but by page 45 are now bordering on paranoia and conspiracy theories. The conspiracy theories are all the more puzzling when the simplest and most reasonable explanation is that the spectre patch has punished Intel processors rather severely. I’ve found trying to argue against conspiracy theories, be it the moon landing or anti-vaxers, to be singularly ineffective.The more you provide scientific evidence and rationality, the harder conspiracy theorists dig in their heels and defend their original position. Our natural confirmatory bias to only seek evidence which confirms pre-existing beliefs seems to be a flaw built into the wiring of the human brain. Psychologically protective? Yes... it’s nice to always be right. Useful for doing science? No.
I’d be delighted (and shocked) in a week’s time to learn of massive incompetence or a cover up. I expect there to be some interesting and unexpected details. But I’m guessing no evidence will be found for the commonly repeated conspiracy theories (spectre effect is minimal, heatsink throttling, bias against intel, etc.). But I guess that will just be further evidence there really is a conspiracy... whatever.
Keep up the good work guys. A long time reader.
RafaelHerschel - Wednesday, April 25, 2018 - link
I think you need more training, psychologist in training, because it seems that you can't detect your own personal bias. As you stated yourself, the original complaints are quite reasonable. The problem is that AnandTech is not addressing these complaints in a timely manner and is mostly interested in damage control.The fact that some complaints are unreasonable doesn't change the fact.
Many other reviewers have applied all relevant patches, it is poor form to assume that they haven't. But I understand why you question their competence or integrity. It's cognitive dissonance. You trust AnandTech. In this case AnandTech is an outlier and has not clarified the unique results of their gaming test. Your trust in AnandTech is therefore not logical, and yet you consider yourself a logical person.
Therefore, you have decided that the 'logical' explanation is that all other reviewers haven't applied the patches... whatever.
divertedpanda - Wednesday, April 25, 2018 - link
Other reviewers admitted having not patched down to the bios since some used mobos where patches were not yet released.TrackSmart - Thursday, April 26, 2018 - link
This comment by RafaelHerschel doesn't make sense. The person being maligned said exactly this: "I expect there to be some interesting and unexpected details. But I’m guessing no evidence will be found for the commonly repeated conspiracy theories..."And he/she was EXACTLY CORRECT in that prediction.
Your complaint, on the other hand, seems disingenuous. Anandtech's staff immediately flagged their gaming results as anomalous (on just about every page of the article). Then they dug deep to figure out what happened, which takes time to test, confirm, and then publish about). Then about 5 days later they posted updated results (2700x and i7-8700k, so far) and a VERY DETAILED explanation of what happened.
So.... What's the problem again? That sometimes unforeseen test parameters can lead to different results? That can happen. The only question is how was the situation handled. In this case, I think reasonably well under the circumstances.
mapesdhs - Monday, May 14, 2018 - link
Grud knows now what "timely manner" is supposed to mean these days. Perhaps RafaelHerschel would only be happy if AT can go back in time and change the article before it's published.Meow.au, re what you said, Stefan Molyneux has some great pieces on these issues on YT.
schlock - Tuesday, April 24, 2018 - link
Why aren't we running DDR4-3200 across all systems? It may go a small ways to explaining the small discrepancy in intel performance ...