AMD Radeon HD 7970: 28nm Tahiti GPU Review

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Total System Power Consumption

Before bringing this article to a close, we'd like to cover a few final data points--namely power consumption and noise. Throughout all of our benchmarking and testing, we monitored acoustics and tracked how much power our test system was consuming using a power meter. Our goal was to give you an idea as to how much power each configuration used while idling and while under a heavy workload. Please keep in mind that we were testing total system power consumption at the outlet here, not just the power drawn by the graphics cards alone.

Total System Power Consumption
Tested at the Outlet

The new Radeon HD 7970 proved to be relatively power-friendly considering its high-end status. While idling at the Windows desktop, out test system pulled down only 127W, besting all other cards by 11 to 43 Watts. And under load, the Radeon HD 7970 actually consumed slightly less power than the Radeon HD 6970, despite offering much better overall performance; a testament to the efficiency of the architecture and TSMC's 28nm process, which seems better off than its 40nm node was at this early stage. There is, however, one more power-related score to mention. The Radeon HD 6970 also offers an even lower idle power state when the card isn't actively sending a signal to a display. If we let our test system sit until the screen blanked, power consumption dropped to only 116w--another 11 watt savings.

With its larger vapor chamber / heatsink, enhanced fan and fan shroud assembly, and relatively modest power characteristics, it should come as no surprise that the Radeon HD 7970 proved to be somewhat quiet in real world use cases. While idling, the card is all but silent. Under load, we never saw the fan spin up past the 30-40% range, which was audible, but definitely on the silent side in comparison to other high-end graphics cards. Should you manually spin the fans up to higher speeds, it can get loud like previous-gen Radeons, but in real-world use that never happened on its own. We'd say the Radeon HD 7970 is somewhat quieter than Radeon HD 6900 series cards, but not quite as quiet as GeForce GTX 500 series products.

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