Monday, November 23rd 2020
AMD to Introduce Adaptive Undervolting to Precision Boost Overdrive for Ryzen 5000
AMD has announced they will be introducing Adaptive Undervolting tools for their precision Boost Overdrive software, available for the latest Ryzen 5000 series CPUs. This feature will be made available come launch of AGESA 1180 on 400-series and 500-series motherboards (estimated availability in early December), and will require a BIOS update to enable at the software level. According to AMD, this tool will dynamically calculate the precise amount of voltage required for a given task, analyzing internal sensors (such as workload, temperature, socket limits) and adapting voltage values on the fly at up to 1000 times a second.
This approach by AMD will bring a new age for CPU undervolting, which usually only allows for users to undervolt their CPU on the basis of the worst-case scenario: usually, the way undervolters work is by incrementally reducing the CPU's voltage and testing for stability via stress applications, gaming, or other specialized applications. This means that the CPU will have adequate juice so as not to fail in these scenarios - but of course, your CPU isn't always (in fact, it's almost never, depending on your specific use-case) using the full CPU processing power; this means that all other workloads where the CPU isn't under 100% utilization still have room for voltage reductions. With AMD's Adaptive Undervolting, this will now become possible.
In the most basic terms possible, this will mean higher CPU longevity (lower voltages means lower stress on the CPU), alongside reduced power consumption - of interest as ecological consciousness becomes more pervasive. However, another very appealing side to this equation is that of increased performance being extracted from your CPU. We all know about that "silicon lottery" effect where differing CPUs will have differing power characteristics; and we also know that CPU manufacturers set base voltages so as to enable the majority of produced CPUs for a given tier (for example, the Ryzen 9 5900X) to operate "sans probleme".
This silicon lottery will soon be able to be taken advantage of by users by using AMD's Adaptive Undervolting, since this means that voltages will be intelligently, dynamically applied according to their particular CPU's power characteristics. Lower voltages across the CPU stress curve will enable for lower temperatures, which could allow for higher boost clocks to be maintained, for longer periods of time, than if the full, original voltage were to be applied.
AMD's Adaptive Undervolting will allow users to define their undervolting characteristics by "stages", with each differing stage accounting for 3-5 millivolts, up to a maximum of 30 stages (this means a maximum undervolt up to 90-150 millivolt). AMD says that enabling this feature could lead to up to 2% higher single-thread performance and up to 10% higher multithread performance, as lower temperatures enable the CPU to more aggressively Boost under these conditions. According to AMD, this undervolting technique shows higher gains the higher number of CCDs (and thusly, of cores) that a given CPU has available in silicon.
AMD has also stated that this is going to be applied to all new processors going forward; back-porting of this technology to pre-Ryzen 5000 CPUs isn't possible as it requires engineering optimizations that were introduced specifically with Ryzen 5000. The Adaptive Undervolting feature will firstly be available via BIOS settings, but AMD plans to bring this feature up to its OS-level Ryzen master utility.
Source:
AnandTech
This approach by AMD will bring a new age for CPU undervolting, which usually only allows for users to undervolt their CPU on the basis of the worst-case scenario: usually, the way undervolters work is by incrementally reducing the CPU's voltage and testing for stability via stress applications, gaming, or other specialized applications. This means that the CPU will have adequate juice so as not to fail in these scenarios - but of course, your CPU isn't always (in fact, it's almost never, depending on your specific use-case) using the full CPU processing power; this means that all other workloads where the CPU isn't under 100% utilization still have room for voltage reductions. With AMD's Adaptive Undervolting, this will now become possible.
AMD's Adaptive Undervolting will allow users to define their undervolting characteristics by "stages", with each differing stage accounting for 3-5 millivolts, up to a maximum of 30 stages (this means a maximum undervolt up to 90-150 millivolt). AMD says that enabling this feature could lead to up to 2% higher single-thread performance and up to 10% higher multithread performance, as lower temperatures enable the CPU to more aggressively Boost under these conditions. According to AMD, this undervolting technique shows higher gains the higher number of CCDs (and thusly, of cores) that a given CPU has available in silicon.
47 Comments on AMD to Introduce Adaptive Undervolting to Precision Boost Overdrive for Ryzen 5000
at a guess, warranty wont cover if PBO is part of the problem
You cant RMA because your chip wont boost higher, or undervolt lower than some overclocker on youtube, etc
But I bet Intel is totally gonna blow everything away with their GPUs... right? :rolleyes:
What does Intel even have at this point?
Simply said; i run my 2700x at stock with a 360mm radiator and 6 fans. In order to keep the CPU constant below 60 degrees i have to slight undervolt. This allows the heat to stay below the 60 degree mark and thus keep the boost constantly on 4.2Ghz. When it passes the 60 degrees, the boost clock will go lower because the way it's designed todo. When i woud'nt undervolt manually (there is some headroom per chip really) it would pass 60 degrees pretty fast and when i do undervolt it will stay below.
So yes; thats how you get more performance out of it. Chips that run cooler btw do require a bit less power in comparison chips that run into their 80 degree mark. I have a older RX580 watercooled on a 240MM rad including 2 fans, which stay constantly below 60 degree mark when gaming. The peak power consumption was 300W knowing it runs from stock 1366Mhz to 1533Mhz which is almost 200Mhz more.
Polaris is'nt a great overclocker perse; it's just memory bandwidth limited in alot of scenarios. But because of the good cooling it allows me to crank up the voltages and keep it below 60 degrees for higher clocks.
Now whomever started this thread down this warranty idiocy is also wrong. The undervolting will become part of the whole PBO thing, default so it will not be considered oc or warranty killing.
All that said, if you overclock you ALREADY FREAKING KNOW IT DOES WHAT IT DOES TO WARRANTY. Complaining and repeating this over and over doesn't change anything. It never stopped ppl from overclocking anyways.
In my 20+ years of building pc's I've never sent a cpu in for RMA.
They haven't actually added more cores though, but 10% multi-thread performance is close to the 12.5% and for a single core max theoretical for a PAM4 type approach is 3.125%, but that doesn't factor in heat and switching efficiencies. Still all things considered it shows AMD could improve this further and eek out a bit more additional performance. They could drop it down to 0.5ms latency eventually perhaps and get a nudge more performance, but as they scale up core count it should add up as well because they have more load distribution to manipulate voltage and heat output further. It's crazy they implemented very similar to what I spoke about, but slightly different round about manner. It's quite fascinating to see how quickly they incorporated this type of behavior and how effective it is. I can see it improving a bit further with more cores and reduced latency. You'll always be retrained by voltage being squared and heat output however. There is defiantly diminishing returns on it very much though. I reasonably see them going to 0.5ms latency in due time on the polling rate checks to dynamically adjust things however or at least 0.75ms latency though both seem plausible.
www.techpowerup.com/forums/threads/first-signs-of-amd-zen-3-vermeer-cpus-surface-ryzen-7-5800x-tested.272715/page-3#post-4359274
A cpu still does the same amount of work at a lower voltage, (provided it isn't undervolted to the point instability.) which means it does the same amount of work, at lower power. And thus lower temps.
A made up, theoretical example is a cpu that can boost to max speed, using 150W, but if it stays at 150W too long it gets too hot and drops down to 140W, lowering performance.
Meanwhile, if the cpu was undervolted, it might be running at 140W at max speed, meaning it can stay at max perpetually.I'm not sure if it can, but not supporting it in warranty means they don't have to deal with the people who might experience the system being too-undervolted and thus be unstable.
After all, if a pc suddenly stops and crashes all the way down to boot while working on something heavy, then that is a very valid cause for concern for many users. As InVasMani points out.
Better to just have it be a blanket ban just-in-case, to avoid having to deal with a ton of consumer support, and people claiming the cpus are bad (because they crashed during high load and too low-voltage.)
I'm very glad that AMD is rolling this out, and I hope intel follows suit.
I've undervolted my last 2 (intel) laptops, and have been very happy with the ~ -10-20% power usage on them. I very much hope dynamic undervolting just becomes one of those standard cpu features everyone has and uses.
Having cpus perform worse and hotter just to increase processor yields in manufacturing is pretty frustrating, and it's good to see that they're finally willing to start playing with it.