7950 gets a quick refresh
Back in June, AMD released (or at least announced) an update to the Radeon HD 7970 3GB card called the GHz Edition. Besides the higher clock speeds, the card was the first AMD offering to include PowerTune with Boost–a dynamic clock scaling capability that allowed the GPU to increase clock speeds when power and temperature allowed.
While similar in ideology to the GPU Boost that NVIDIA invented with the GTX 680 Kepler launch, AMD's Boost is completely predictable and repeatable. Everyone's HD 7970 GHz Edition performs exactly the same regardless of your system or environment.
Here is some commentary that I had on the technology back in June that remains unchanged:
AMD's PowerTune with Boost technology differs from NVIDIA's GPU Boost in a couple of important ways. First, much to its original premise, AMD can guarantee exactly how all Radeon HD 7970 3GB GHz Edition graphics cards will operate, and at what speeds in any given environment. There should be no variability between the card that I get and the card that you can buy online. Using digital temperature estimation in conjunction with voltage control, the PowerTune implementation of boost is completely deterministic.
As the above diagram illustrates, the "new" part of PowerTune with the GHz Edition is the ability to vary the voltage of the GPU in real-time to address a wider range of qualified clock speeds. On the previous HD 7970s the voltage was a locked static voltage in its performance mode, meaning that it would not increase or decrease during load operations. As AMD stated to us in a conversation just prior to launch, "by having multiple voltages that can be invoked, we can be at a more optimal clock/voltage combination more of the time, and deliver higher average performance."
The problem I have with AMD's boost technology is that they are obviously implementing this as a reaction to NVIDIA's technology. That isn't necessarily a bad thing, but the tech feels a little premature because of it. We were provided no tools prior to launch to actually monitor the exact clock speed of the GPU in real-time. The ability to monitor these very small changes in clock speed are paramount to our ability to verify the company's claims, and without it we will have questions about the validity of results. GPU-Z and other applications we usually use to monitor clock speeds (including AMD's driver) only report 1050 MHz as the clock speed–no real-time dynamic changes are being reported.
(As a side note, AMD has promised to showcase their internal tool to show real-time clock speed changes in our Live Review at http://pcper.com/live on Friday the 22nd, 11am PDT / 2pm EDT.) [It has since been archived for your viewing pleasure.]
A couple of points to make here: AMD still has not released that tool to show us internal steps of clock speeds, and instead told me today that they were waiting for an updated API to allow other software (including their own CCC) to be able to report the precise results.
Today AMD is letting us preview the new HD 7950 3GB card that will be shipping soon with updated clock speeds and Boost support. The new base clock speed of the HD 7950 will be 850 MHz, compared to the 800 MHz of the original reference HD 7950. The GPU will be able to boost as high as 925 MHz. That should give the new 7950s a solid performance gain over the original with a clock speed increase of as much as 15%.
Get notified when we go live!