Reaching for Turbo: Aligning Perception with AMD’s Frequency Metrics
by Dr. Ian Cutress on September 17, 2019 10:00 AM ESTDo Manufacturers Guarantee Turbo Frequencies?
The question: ‘do manufacturers guarantee turbo frequencies?’ seems like it has an obvious answer to a lot of people. I performed a poll on my private twitter, and the voting results (700+) were astonishing.
Testing my audience's knowledge. Is the CPU Turbo Frequency on a desktop processor guaranteed by the manufacturer? Yes or No? [POLL]
— Dr. Ian Cutress (@IanCutress) September 12, 2019
31% of people said yes, 69% of people said no.
The correct answer is No, Turbo is never guaranteed.
To clarify, we need to define guarantee:
"A formal assurance that certain conditions will be fulfilled - if pertaining to a product, then that product will be repaired or replaced if not the specified quality."
This means that under a guarantee, the manufacturer would be prepared to repair or replace the product if it did not meet that guarantee. By that definition, Turbo is in no way under the guarantee from the manufacturer and does not fall under warranty.
Both AMD and Intel guarantee four things with their hardware: core counts, base frequency, peak power consumption at that base frequency (in essence, the TDP, even though strictly speaking TDP isn’t a measure of power consumption, but it is approximate), and the length of time those other items are guaranteed to work (usually three years in most locales). If you buy a 6 core CPU and only four cores work, you can get it replaced. If that six core CPU does not hit the base frequency under standard operations (standard is defined be Intel and AMD here, usually with a stock cooler, new paste, a clean chassis with active airflow of a minimum rate, and a given ambient temperature), then you can get it replaced.
Turbo, in this instance, is aspirational. We typically talk about things like ‘a 4.4 GHz Turbo frequency’, when technically we should be stating ‘up to 4.4 GHz Turbo frequency’. The ‘up to’ part is just as important as the rest, and the press (me included) is guilty of not mentioning the fact more often. Both Intel and AMD state that their processors under normal conditions should hit the turbo frequency, and both companies actively promote frequency enhancing tools such as aggressive power modes or better turbo profiles, but in no way is any of this actually guaranteed.
Yes, it does kind of suck (that’s the technical term). Both companies market their turbo frequencies loudly, proudly, and sometimes erroneously. Saying something is the ‘first X GHz’ processor only really means something if you can actually get into a position where that frequency is guaranteed. Unscrupulous retailers even put the turbo frequency as the highlight in their marketing material. Trying to explain to the casual user that this turbo frequency, this value that’s plastered everywhere, isn’t actually covered by the warranty, isn’t a good way to encourage them to get a processor.
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peevee - Friday, September 20, 2019 - link
Sunny Cove is about just as new as Zen2 compared to Zen+, if not more.Only not "architecture" but "microarchitecture", architecture is the same Von Neumann prevalent since 1940s, or its Harvard variant prevalent since 1980s.
Jovec - Tuesday, September 17, 2019 - link
Might go to credibility and past behavior. Bulldozer couldn't maintain stock speeds under load (although the lawsuit was for something else IIRC).evilspoons - Tuesday, September 17, 2019 - link
Thanks for the informative article. The modal frequency being so close to the rating on all those 3000-series chips, BEFORE the +25-50 MHz fix, means it's not even worth worrying about. As consumers it's good to be informed and keep an eye on the companies we buy from, but there's no conspiracy here. Just confusion.Karmena - Wednesday, September 18, 2019 - link
Companies have to be held accountable on what they write on the boxes. Even if that is off by 25 out of 4400. Just be honest and write 4375.Atari2600 - Wednesday, September 18, 2019 - link
I'm sure your bright enough to be able to round up to 1 decimal place.What does 4.375 become when rounded to 1 decimal place?
ianisiam - Wednesday, September 18, 2019 - link
Except for the fact that 4400 isn't guaranteed. Like evilspoons said, it's just confusion.eva02langley - Wednesday, September 18, 2019 - link
You didn`t read the article obviously... these are not guaranteed. If you apply thermal paste and HSF pressure like an amateur, your results will not be in line with AMD numbers, but of course you will scream rip-off...Karmena - Monday, September 23, 2019 - link
Will not scream, just it would be nice to have every little bit. With ABBA, that is the case, in the end I need good mobo, good cooling, some memory OC prooves and I do not have to worry about CPU OC as that is brought to maximum performance by itself already.limitedaccess - Tuesday, September 17, 2019 - link
I feel there is one more aspect to this that wasn't fully addressed nor have seen it very addressed in discussions.According to your article (which matches previous understanding) is that Intel (even if they won't guarantee it the boost speeds) will bin CPUs so that every core is capable of running at the listed turbo speeds. In your example every core can reach 4.6ghz for the 9600k.
While AMD with Zen is only binning one core as capable of reaching the boost speeds. Although you list a more likely typical example in your article does this not in theory mean that a 3600x which can only reach 4.4ghz on a single core, while all other 7 can only hit 3.8ghz will pass (even if statistically such a CPU is extremely unlikely)? Or is their binning actually tighter then this but not disclosed anywhere?
This has been one of my concerns with respect the this type of situation going forward. It seems like there needs to be more disclosure/data points on binning requirements going forward.
ajlueke - Tuesday, September 17, 2019 - link
Thanks Ian!Could you highlight what the nebulous "limits of the silicon" are? I have noticed, that in low current (core) work loads with Zen 2, the performance seems to be fixed. I'm not reaching any temperature, EDC, TDC or PPT boundary, but changing the scalar, increasing fmax, or increasing the aforementioned limits. It seems something else is limiting the processor's ability to boost, but there is no clear indication what that is. I have observed the Stilt mention the Fitness Monitoring Tool (FIT) as a voltage limit baked into the silicon. Zen 2, tend to be at this limit, and it simply will not go higher regardless of what you set PPT, TDC and EDC at. Do you have any additional information on this limiter?
It does seem fundamentally different for overclockers. The voltage limit on boosting seems to be reached before thermal limits, meaning that Zen2 CPUs with the stock cooler boost the same as those with far better heat dissipation, at least in lightly threaded workloads. I guess this is a good thing for users overall, as everyone gets the same performance out of the box, but jarring for enthusiasts who are used to seeing much high numbers on their systems. I noticed the delta between the bottom 5th percentile and upper 95th percentile of the 3900X on userbenchmark was 12.4%. Incredibly tight, and demonstrates that there likely isn't much to ring out of these systems.