XFX Double D HD 7970 GHz Edition Video Card Review

With continuous AMD price drops the XFX Double D HD 7970 GHz Edition video card has dropped into line with many of NVIDIA's GeForce GTX 670 cards. Find out if the XFX's Double Dissipation technology will excel this video cards overclocking potential when we put it head to head with GeForce GTX 680 and overclocked GeForce GTX 670.

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Overclocking the XFX Double D HD 7970 GHz Edition Video Card

Throughout this evaluation we will be using our highest stable overclock after voltage tweaking as a fourth video card in the evaluation, in order to fully express the amount of performance that the XFX Double D HD 7970 GHz Edition has in store.

Please remember that every video card is different and the overclocks we achieve here are not necessarily what you will be able to achieve.

The actual overclocking procedure involved increasing the GPU clock speed until errors occurred, and then backing it down until the errors stopped. Overclocking the GDDR5 memory is a bit more complicated. GDDR5 has error detection and correction technology which actually adjusts the clock-rate down in order to stop errors from happening. To overclock the memory on this video card, we simply turned the clock rate until performance diminished, and then backed it back off slowly until performance stabilized.


Overclocking with AMD Overdrive

To overclock the XFX Double D HD 7970 GHz Edition we are using AMD Overdrive which is built in to the Catalyst Control Panel. You can find this after installing the latest driver software and navigating to the performance tab inside of CCC.

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The first thing we did in order to overclock the XFX Double D HD 7970 GHz Edition was to increase PowerTune to +20% and set the fans to the highest speed in order to dissipate any extra heat being generated. The fans on automatic handled keeping the heat off without any issue after we achieved our highest overclock.

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After enabling +20% PowerTune we proceeded to increase the GPU speed until performance diminished. We found that the video card was stable at 1210MHz. Anywhere past 1210MHz the video card started creating visual anomalies and failed to load some textures. This was an increase of 160MHz compared to the stock operating speeds. Next we needed to increase the memory as far as possible. We found that this frequency was 1715MHz, an increase of 215MHz which allowed the memory to run at 6.86GHz GDDR5.

We also downloaded other third party software in hopes of being able to change the voltages of the card. With MSI Afterburner we had the option to enable 1.3 volts up from 1.2V. This did not allow us to get any farther in overclocking, and did not show any increased power draw on our Kill-A-Watt reader. Because this did not effectively increase the boards power we were left with the overclock from AMD Overdrive as our highest overclock.

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As mentioned the XFX Double D HD 7970 GHz Edition does not have a factory overclock, meaning it runs at the standard Radeon HD 7970 GHz Edition speeds of 1050MHz on the GPU and the memory running at 6GHz. After manually overclocking the XFX Double D HD 7970 GHz Edition we reached a operating speed of 1210MHz on the GPU which was an overall increase of 160MHz compared to the reference model. The memory also increased by 215MHz, from 1500MHz up to 1715MHz or 6.86GHz GDDR5.

Below is a screenshot of GPU-Z after achieving our highest stable overclock on the XFX Double D HD 7970 GHz Edition video card. We will be using this operating frequency as a fourth video card in this evaluation.

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