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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ajlueke - Tuesday, September 17, 2019 - link
More specifically, I was referring to this test from the article."Because of the new binning strategy – and despite what some of AMD's poorly executed marketing material has been saying – PBO hasn't been having the same effect, and users are seeing little-to-no benefit. This isn’t because PBO is failing, it’s because the CPU out of the box is already near its peak limits, and AMD’s metrics from manufacturing state that the CPU has a lifespan that AMD is happy with despite being near silicon limits."
What silicon limits exactly? AMDs marketing material has always indicated that a CPU will boost until it reaches either the PPT, TDC, EDC, or thermal limits. If none of those are met, it will boost until Fmax, which it simply will not exceed. Now, in a single threaded workload, the user is almost never at a PPT,TDC, EDC or thermal limit, and seem to be just shy of Fmax anyway. Now, if the user enables the auto-oc feature and extends Fmax by 100, 150 or 200MHz...nothing happens. The identical clockspeed and performance are observed.
I see the same thing happen in multicore on my 3900X. I normally hits the EDC and PPT limits under standard boosting. If I remove them, with precision boost overdrive, it does boost higher, but not by much. It again seems to stop a certain point. Again, EDC, TDC and PPT motherboard limits are not met, I am certainly not at Fmax, and the chip is under 70C, but it stops nonetheless. Nothing I can do makes it boost further.
"The Stilt", seems to mention the silicon fitness monitoring feature (FIT) in his "Matisse Strictly Technical" post on overclock.net. FIT appears to be a specific voltage limit for high and low current the CPU cannot exceed. This has never been included in AMDs documentation, and would help explain why the processor's stop boosting when according to AMD's own documentation, they should keep on going. So what exactly is this feature, and how does it work? I think that answer would do a great deal to alleviate user confusion.
mabellon - Tuesday, September 17, 2019 - link
>> "To a certain extent, Intel already kind of does this with its Turbo Boost Max 3.0 processors... [the] difference between the two companies is that AMD has essentially applied this idea chip-wide and through its product stack, while Intel has not, potentially leaving out-of-the-box performance on the table."What does this mean? What has Intel not done that AMD has done? Both have variable max frequency per core. Both expose this concept to the OS. Both rely on the same Window scheduler. What are you alluding to is different here?
It seems to me that Intel's HEDT platform with Turbo 3.0 is very much similar to AMD's implementation in the sense of having certain cores run faster. @Ian how is performance left on the table for Intel here? (Intel non HEDT is obviously stuck on Turbo 2.0 which is at a disadvantage)
Targon - Tuesday, September 17, 2019 - link
The majority of Intel chips are multiplier locked, so there isn't any real overclocking ability to speak of. It is only the k chips that users can overclock. AMD on the other hand, has PBO which is more advanced when it comes down to it.edzieba - Thursday, September 19, 2019 - link
"What does this mean? What has Intel not done that AMD has done?"Intel picks the maximum 'turbo' bin as the lowest that any core can achieve. AMD picks their maximum boost bin as the highest that any single core could achieve. 'Turbo 3.0' pre-selected two cores that were able to clock above the all-core turbo bin and allowed them to clock higher for lightly threaded workloads.
Jaxidian - Tuesday, September 17, 2019 - link
Is this WSL tool available for us to use? I'd love to have a better view of what speeds my cores could hit with a tool like this. In fact, I'd probably use it to map out all 12 cores (disabling 11 of them at a time). Obviously even that wouldn't quite give the whole picture, but it would be an interesting baseline map to have for my 3900x chip.Jaxidian - Tuesday, September 17, 2019 - link
I got my "no" answer here: https://twitter.com/IanCutress/status/117401405985..."It's a custom kludgy thing for internal use."
MFinn3333 - Tuesday, September 17, 2019 - link
I miss the old days when I would just push the Turbo frequency on my 286 and the CPU would go from 10MHz to 12MHz. Sure occassionally chip poppped off from the Glue but it was totally worth it to play Dune 2.sing_electric - Tuesday, September 17, 2019 - link
"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’."This is true, but EXACTLY the problem. The marketing teams at AMD, Intel and everyone else KNOW that when you see "3.6 GHz / 4.5 GHZ Turbo" written on a box, your eye falls to the second, larger number, and that's what sticks in your head.
Why should the consumer know that some of the numbers on the box (core count, base freq) are guaranteed, but some (turbo) aren't? That makes no sense and is borderline deceptive. And this doesn't just matter to the fairly small, tech savvy group of people who buy a processor alone in a box - here's how Dell lists the processor on its base config XPS 13 laptop when you go to "Tech Specs & Customization"
"8th Generation Intel® Core™ i5-8265U Processor (6M Cache, up to 3.9 GHz, 4 cores)"
Dell doesn't even bother LISTING the base frequency, even when you click to get more detail - how's a consumer supposed to gauge how fast their processor is? (To their credit, Apple, HP and Lenovo all list base frequency and "up to" the turbo).
Turbo is a great technology for getting the most out of limited silicon, but both AMD and Intel are, while not QUITE being untruthful, certainly trying to put their products in as good of a light as possible.
DigitalFreak - Tuesday, September 17, 2019 - link
That's marketing for you. Step as close to the "deceive the customer" line as possible without getting sued.Jaxidian - Tuesday, September 17, 2019 - link
I'm looking at the retail box for my 3900x right now. The only thing it says about frequencies is "4.6 GHz Max Boost, 3.8 GHz Base". There is no "up to" verbiage anywhere on the box. From a FTC advertising standpoint, the 4.6GHz should be guaranteed even if only under nuanced "limited single-core" and "with specific but reasonable motherboard, cooling, and software" scenarios.While this is a very good article and I generally have very few issues with AMD's new approach here, I'm of the belief that legally, a 3900x should be guaranteed to hit 4.6GHz when in a specific-yet-real-world scenario. I don't mean $100 mobos with $25 coolers should be able to hit it. But a better-than-budget x570 motherboard using the stock cooler with proper updates on a supported OS should absolutely hit 4.6GHz with certain loads. Otherwise, I think there's a real legal issue here.
All this said, I am now seeing 4.6GHz from time to time on my 3900x with ABBA on my x570 Aorus Master, so we're good here. Never saw higher than 4.575 before ABBA.