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.
Facebook
Twitter
RSS
92 Comments
View All Comments
web2dot0 - Wednesday, March 2, 2022 - link
PC fanbois would pretend M1 isn't in the convo.😆
They will just tell you that nobody cares about performance per watt... because they said so.
Qasar - Wednesday, March 2, 2022 - link
and the apple fanboys just keep talking about the m1 like its the best things since sliced bread, whats your point ?bottom line is this, IF you are already using the over priced apple eco system, then the m1 makes sense, if not, then there is no point to it. i only know 3 people that have either an ipad, or a mac based comp, the rest wont touch apple cause of the price, too expensive for what they would need it for, windows based products, suit their needs just fine.
schujj07 - Wednesday, March 2, 2022 - link
For sure Apple is way too expensive for what you get. Working in industry I hate it when I have to give support to someone using a Mac because the VPN we send them doesn't work. Of the hundreds of VPNs I have sent to people, less then 10 have responded to me saying they need the one for Mac. Mac just doesn't play as nicely with the things we use in a lot of IT.Obiwanbilly - Friday, March 4, 2022 - link
Oh, the VPN doesn’t work? I have an M1 MacBook Air and I use WireGuard for my VPN. It works perfect!Oh 🤔, do you mean “Legacy” VPNs, that are based on IPSEC or OpenVPN? You know, the one’s where Wikipedia says, “… are often complex to set up, disconnect easily (in the absence of further configuration), take substantial time to negotiate reconnections, may use outdated ciphers, and have relatively massive code bases of over 400,000 and 600,000 lines of code, respectively, which hinders debugging.“
That one? 👆😱
Hey bro, some of us Mac users are “Pros” too. Maybe you should stop using legacy VPN software and switch to something better? Instead of blaming Macs! 🤦♂️
Obiwanbill
BushLin - Friday, March 4, 2022 - link
Try connecting to your employer's VPN, chances are that it's not wireguard.Obiwanbilly - Friday, March 4, 2022 - link
Yep, it’s legacy. It needs to be upgraded. I can help, if you want. 😬I don’t know why you would continue to use OpenVPN or IPSec. I first used that tech like 14 yrs ago. Move on! 🤓
Go research the benefits of using WireGuard. It’s a waaaay better solution. Dropped connections on IPSec or Open VPN take FOREVER to reconnect. You don’t need licenses, you can support unlimited users. Your limitation is the hardware you choose to host your WireGuard Server endpoint. WireGuard supports Windows and Android endpoint client devices. Oh yeah, and Mac OS too. 🥳
ObiwanBilly
Dug - Friday, March 11, 2022 - link
Then you have an outdated or crappy vpn. Every industry standard has a mac client that works fine. Even Azure has a mac configuration for mac vpn.wolfesteinabhi - Wednesday, March 2, 2022 - link
it will be in convo when Apple starts selling Windows "PC" with M1 in it. till then its definitely not in Convo.tyger11 - Thursday, March 3, 2022 - link
OS X is enough to keep me away from that hardware, so it doesn't matter.GeoffreyA - Thursday, March 3, 2022 - link
Frieza's stronger than Goku right now---