AMD's Ryzen 9 6900HS Rembrandt Benchmarked: Zen3+ Power and Performance Scaling
by Dr. Ian Cutress on March 1, 2022 9:30 AM ESTPerformance Per Watt
With the ASUS Zephyrus G14, it comes with some fancy ASUS software called the Armo(u)ry Crate. Inside is the usual array of options for a modern laptop when it comes to performance profiles, fans, special RGB effects and lighting, information about voltages, frequencies, fan speeds, fan profiles, and all that jazz. However inside the software there is also an interface that allows the user to cap how much APU/SoC power can be put through the processor or the whole platform.
With this option, we took advantage of the fact that the after we select a given SoC wattage, the system will automatically migrate to the required voltage and frequency under load while only ever going up to the power limits - or as much as the system would be allowed to. Using this tool, we ran a spectrum of performance data against power options to see how the POV-Ray benchmark would scale, as it is one of the benchmarks that drives core use very high and very hard.
In this first graph, we monitor how the CPU voltage increases by raising the power, as well as the at-load temperature of the processor. The voltage increments start off around the 60-65 mW per 5W of SoC power, eventually becoming 15-25 W due to the way that voltage and power scales. The temperature was a very constant rise, showing 96ºC with the full 80 W selected.
Now if we transition this to the benchmark results, as we plot this with the all-core frequency as well:
These two lines follow a similar pattern, as the score doesn't increase if the frequency doesn't increase. The biggest jumps are in the 15-35W mark, which is where most modern processors are the most efficient. However as the power is added in, the processor moves away from that ideal efficiency point, and going from 50 W to 80 W is a 60% power increase for only +375 MHz and only +7.7% increased score in the benchmark.
We can pivot this data into something a bit more familiar:
Here we can see the voltage required for all-core frequencies and how the voltage scales up. With all this data, we can actually do a performance per watt graph for Rembrandt:
In this graph we're plotting Score per watt against Frequency, and it showcases that beyond 2.5 GHz, the Rembrandt CPU design becomes less efficient. Most modern processors end up being most efficient around this frequency, so it isn't perhaps all that surprising.
Now all of this is also subject to binning - not only are chips binned by the designation (6900HS vs 6800H for example), but also within an individual SKU, there will be better bins than others. We see this in some mobile processors that can have 10+ bins with different voltage/frequency characteristics, but all still called the same, because they perform at a shared guaranteed minimum. With smartphones, this testing is a lot easier, as that voltage/frequency table is often part of the hardware mechanism. But for notebooks and desktops, we're often at the mercy of the motherboard manufacturer or OEM, who can use their own settings, overriding anything that Intel or AMD suggest. Hopefully in the future we will get more control and be able to determine what is manufacturer based and what is motherboard based.
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mode_13h - Thursday, March 24, 2022 - link
> Mulholland Drive is perhaps my favourite film of all films.After your last post, I was already going to start (re-)watching Lynch's films, but maybe I'll start there.
GeoffreyA - Monday, March 28, 2022 - link
MD is the best. All his other films tend to be something of a mess or too obscure or too excessive. In particular, I despise Lost Highway. Straight Story is good for the whole family though, and Elephant Man.GeoffreyA - Monday, March 28, 2022 - link
Another film I love is Kieslowski's "Trois couleurs rouge" (Three Colours: Red).mode_13h - Wednesday, March 30, 2022 - link
I saw Red, long ago. I remember it made an impression on me, but not much else.I remember watching bits of Elephant Man with my parents, but they rented and watched it at home and I think I was too young to really sit and watch the whole thing.
Never saw Lost Highway, but I think one of the first MP3s I got was a rip of the Trent Reznor song from it + remixes.
Heh, I just watched the documentary: Jodorowsky's Dune. What a trippy guy! He literally cast Salvador Dali as the Emperor and seems to have been H.R. Geiger's route into the movie business. We can probably thank the fact that he cast Mick Jagger as Feyd-Rautha as the reason Sting ended up in Lynch's version.
I think it's safe to say it would've been a *very* different movie. He seemed most fascinated by the aspects of the book that least impressed me (i.e. the mysticism and psychedelic stuff). He said he wanted the movie to seem like a long acid trip and even admitted to changing the ending. Unapologetically. He's *that* kind of film maker ...which is okay, but just not if you're a fan of the book.
GeoffreyA - Friday, April 1, 2022 - link
The first time I saw Red, I didn't think much of it, except that it was very polished stylistically; but it's the sort of film that gains a lot from repeat viewings, and possesses a beautiful symmetry and design. It seems to distill, in a simpler fashion, the "plot" we sometimes see in life.I've often heard about Jodorowsky's Dune and need to watch that documentary. Well, if Geiger's designs were supposed to be there, it would've been a striking movie, that's for sure! I get the feeling I might have actually enjoyed it. Anyhow, looks as if the faithful Dune adaptation is still to be made. Where is this mighty director?
GeoffreyA - Friday, April 1, 2022 - link
(Come to think of it, DeMille might have done a good job.)mode_13h - Saturday, April 2, 2022 - link
> I've often heard about Jodorowsky's Dune and need to watch that documentary.You'd get a little more from the documentary if you'd read the book, first. Otherwise, you wouldn't have as much appreciation for the aspects of the book that attracted him. Plus, there's a bit of a spoiler, later in the documentary, where he talks about how he was going to change the ending.
GeoffreyA - Sunday, April 3, 2022 - link
I see. Thanks for that warning!Violet Giraffe - Friday, March 11, 2022 - link
Are you mad? Apple is at least a year behind the real CPU manufacturers. And Zen 4 will leave it on the side of the road.Violet Giraffe - Friday, March 11, 2022 - link
M1 is cute, nothing more. It's GPU is relatively powerful compared to other mobile chips, otherwise it sucks. I have an M1 Mac Mini so it's first-hand experience.