Articles

AMD Radeon VII Chilling & Undervolting

Author:Brent Justice

Date: Sunday , February 24, 2019

Is anyway to improve Radeon VII power efficiency, GPU temperature, and fan noise without drastically changing the gameplay experience. Is Radeon Chill or GPU undervolting the answer? We run the Radeon VII through some real world gaming and show you exactly what Chill and Undervolting will do to, or for your gameplay.

Introduction

On February 7th, 2019 AMD launched the Radeon VII video card with an MSRP of $699.99. On February 14th, 2019 we published our full video card review on the AMD Radeon VII. In our review we compared the video card at both 1440p and 4K resolutions in eight of today’s latest games. Our comparison consisted fairly of an equally priced $699 MSI GeForce RTX 2080 VENTUS video card and the more expensive, but also competitive, NVIDIA GeForce RTX 2080 Founders Edition.

Our review revealed many truths about real-world gameplay with the AMD Radeon VII. It wins in some, and looses in others, sometimes it’s even with GeForce RTX 2080. One thing is for certain, the AMD Radeon VII is a big leap in performance from the AMD Radeon Vega 64 even though it utilizes less compute units and stream processors versus Vega 64. This is achieved through its new 7nm manufacturing process and massively increased clock speeds with some evolutionary GPU architecture tweaks.

One aspect of performance that has plagued AMD for several years now has been its power and temperature profiles compared to the competition. The competition has had more efficient architecture designs which yield better efficiency in terms of power and temperature. You basically get more performance, for less wattage with the competition. This has been the status quo for quite a while.

With the AMD Radeon VII AMD is once again pushing the architecture as hard as possible, a brute force approach you could say, to improve performance through large clock speed increases with appropriate voltages. Even with the improved 7nm manufacturing process the architecture can only be pushed so far. We are in high need of a new architecture from AMD, and they know it too. Until Navi comes, Radeon VII is pushing the Vega architecture to the extreme. As such, the power demand and temperatures (and thus fan noise) may not be quite what people expected. In that regard, we wanted to test a couple of different popular options to reducing power draw and temperatures and thus fan noise.

There is a built-in option in the drivers called AMD Radeon Chill. So, we are going to test this. The other option is a bit of a "more enthusiast" option that requires some time and effort, and that is GPU undervolting. Therefore, we are going to try that as well. Our goal is to find out if there is a performance loss from these methods, and how that impacts gameplay. We are also going to see which method produces the best results in terms of power savings and temperature savings, thus reducing fan noise as well.


AMD Radeon Chill

AMD Radeon Chill was introduced into the drivers as far back as late 2016. Over time it has received many updates, including now support for DX9/10/11/12 and Vulkan API. It is now very robust, and just works very well in every game. This feature works simply by reducing framerate which in turn reduces power and possibly temperature and fan noise as well. It works by detecting lessened movement via mouse and keyboard inputs.

This means in games where you may be more lax on direct control, or moments where you aren’t rapidly spamming the keyboard and mouse could results in better power savings while gaming. If something on the screen isn’t changing as fast, then the GPU doesn’t need to work as hard, in theory. There is a lot more to this technology, it is very intelligent, but for the purpose of this evaluation we are simply going to use the feature and compare it to GPU undervolting.

To enable Radeon Chill is twofold. You must first go into the drivers under Gaming and Global Graphics Settings. You then must turn on "Chill." You can bind a hotkey to enable you to disable it on the fly in-game to see the differences live. After you turn it on for each game it is turned on by default when you launch the game, the hotkey will disable it in-game, and then re-enable it. There is also an audible alert this being turned on and off as well.

The next step you must scan your computer for games, or let Radeon Software scan your computer for games installed. You then have to go to each individual game in the driver and turn on Radeon Chill in that game. In the game settings in Radeon Software you will see "Chill (FPS)" option. You have to turn this on. Once you do so there will be a default minimum and maximum chill FPS setting. The default is 70FPS minimum and 144FPS maximum. The definition of these settings is thus:

Chill MIN - The minimum framerate for chill to function within (the minimum is 30 FPS, the default value is 70.)

Chill MAX - The maximum frame rate for chill to function within (the maximum is 300 FPS, the default value is 144.)

This page will give you more info on how to use Chill.


GPU Undervolting

A tried and true method for hardware enthusiasts has always been GPU undervolting. This can result in many different outcomes. On one hand GPU voltage undervolting can result in lessened power demand, lessened GPU temperature, and lessened fan noise. On the other hand, it could remove a bottleneck associated with the TDP of the video card and thus actually improve performance by allowing the GPU clock speed to run higher and more consistent.

Sometimes the default voltage is so high that the GPU clock speed isn’t always automatically clocking as high as it could if thermals and power were reduced via undervolting. The question is, what will happen with Radeon VII? This is a new video card; a new GPU and we don’t know just yet what GPU undervolting will do to it. Therefore, in this review, we will find out! Will it reduce power? Will it reduce performance? Will it reduce temperature and fan noise? Or will it improve performance?

To manipulate GPU voltage is easy within AMD Radeon Wattman. You simply toggle the Frequency/Voltage option to Manual and are allowed to adjust both. By default, the frequency is set around 1801-1802MHz with a voltage of 1084mv (1.084V) maximum.

Note that there is an "Auto Undervolt GPU" option in the Tuning Control section. We first tried this option to see how well it works. Unfortunately for us this option caused every single game I ran to crash upon launching. (Interestingly, Kyle's Radeon VII card works just fine with Auto Undervolting, with a good showing.) Hopefully this is just a driver issue, and not a card issue. A new BIOS as well as drivers have been released since we did all our testing here. We have experienced many Wattman bugs since the Radeon VII launch. Note that we are using the official 19.2.2 drivers released on 2/13 from AMD.com for this review.

The only option for us was to manually adjust the GPU voltage as low as possible and still maintain stability in every game. We tried setting the voltage as far down as 950mv, which instantly crashed for us. We then moved up until we had stability in every single game in our test suite. We actually found 980mv worked in most games, but when we tried to play Wolfenstein II for more than five minutes it would crash. Therefore, we ended up moving it up to 990mv and then it worked just fine. Therefore, 990mv is our lowest stable voltage we could attain with every single game being stable. This is a reduction of 94mv, almost .1 volt. When you see the data showing (Undervolting) on the graphs this is at 990mv.

We are also using the built in Performance Monitoring from AMD to log all the power/temperature results. We have the time set at one second intervals.

That is all the changes we made, we did not manipulate fan speed or power target or anything else, just a simple voltage reduction.