- Date:
- Monday , January 09, 2012
- Author:
- Brent Justice
- Editor:
- Kyle Bennett
- Share:

AMD Radeon HD 7970 Overclocking Performance Review
We overclock the Radeon HD 7970 in Overdrive and show you what 1.125GHz of performance looks like. Then, we go to the edge and overclock the voltage and take this GPU past 1.2GHz for stellar overclocked gaming performance. We compare this to an overclocked GeForce GTX 580 and see how performance stacks up.
Introduction
On December 22nd, 2011 AMD announced the new AMD Radeon HD 7970 video card, to supplant the Radeon HD 6970 as AMD's fastest single-GPU video card. The AMD Radeon HD 7970 is officially released into retail today. The AMD Radeon HD 7970 is based on a new architecture and a new 28nm manufacturing process.
In our evaluation we experienced a large and noticeable performance improvement over the Radeon HD 6970 and an overclocked GeForce GTX 580. The gameplay experience was better with the Radeon HD 7970 in every game we tested, allowing for better visual quality in games. One area we did not have time to touch on in that evaluation with this video card was overclocking potential and performance.
At AMD's press briefing it was stated that the Radeon HD 7970 should have a lot of headroom. The default core clock is 925MHz on the Radeon HD 7970 in its reference version. Today, we are going to test overclocking and see how far we can push our stock Radeon HD 7970. We will also look at the performance advantages in comparison to stock 7970 speeds as well as the overclocked GTX 580. Power and temp will also be tested.
Overclocking with Overdrive
The easiest way to begin overclocking the Radeon HD 7970 is to use AMD's built in Overdrive option in Catalyst Control Center. Above you can see the Overdrive menu, you will be able to watch the GPU activity, GPU clock speed, Memory clock, Power, Temperature and Fan Speed. This is a great tool built into CCC, however, it does have its limitations. Firstly, it is capped at rather low maximum frequency numbers. For example, the highest core GPU clock you can set is 1125MHz, and the highest memory clock you can set is 1375MHz. As you will soon see, those limits are tame for the Radeon HD 7970, as it is able to go past these. Overdrive is limiting the potential performance advantages of the Radeon HD 7970.
When overclocking, there is one important slider you must set no matter what program you are using to overclock. You will maximize the Power Control Settings to +20% when overclocking any AMD Radeon video card. This will allow the video card to have a higher maintainable TDP, and in result, better performance. We've seen past video cards where this has been an issue, and we have overclocked with little performance gain. When we maxed out this slider, then the overclocking performance we were looking for was there.
Here we have set Overdrive to the highest values, which were 100% stable on the Radeon HD 7970. We stress tested the video card for an entire day at these settings, at stock voltages, and it didn't flinch once. We were able to play all of our games with no issues. We felt after this that there was a lot more potential locked up inside the Radeon HD 7970 just waiting to come out.
On the next couple of pages we will first show you our overclocking results at the maximum Overdrive overclock, so you can see what you can experience at stock voltages with little effort. Following that, we will take the card to the highest we can, as shown below.
Custom Overclocking with Voltage Tweaking
Inherently, Overdrive does not allow Voltage tweaking, or to exceed the values shown below. However, during the course of this evaluation Sapphire dropped us a brand new version of the TRIXX Utility, which we here have found a great program for overclocking. This new version of TRIXX, specified right now to be used for in-house testing, and is not ready for public yet, supports the Radeon HD 7970 and allows us to far exceed Overdrive's limitations. It also allows us to overclock the Voltage on the Radeon HD 7970 to see how high we can really push it. Therefore, we used this program to perform maximum overclocking, we can't show you the screenshots from TRIXX yet, but we can show you GPUz and Overdrive which shows the speeds used.
Through great trial and error, and days of testing, we settled on this overclock as our highest stable overclock with Voltage tweaking. We had to set the Voltage slider to the highest value, which was 1.3V in order to achieve this Overclock. In addition, we had to manually set the fan to 75% to keep the GPU cool enough. At 75% the fan was very loud and annoying, but it allowed us to achieve this high overclock. Also, we did have the power settings at +20%, don't forget this when overclocking.
Our highest stable overclock at 1.3V is 1.260GHz GPU and 6.9GHz memory! This is an absolutely amazing feat, and the performance gains are huge. After we show you the overclocking performance results with Overdrive, the next pages will show the Overclocking performance at this higher overclock.





