Energy consumptionWe used the test protocol that allows us to measure the energy consumption of the graphics card alone. We took these readings at idle on the Windows 7 desktop as well as with the screen in standby so as to observe the impact of ZeroCore Power. In load, we took our readings in Anno 2070, at 1080p with all the settings pushed to their max, and in Battlefield 3, at 1080p in High mode:
While our Radeon HD 7970 GHz Edition is particularly economical at idle, which means that it is only very slightly affected by current leakage, its energy consumption in load is significantly higher than the original Radeon HD 7970.
We've shown the energy consumption readings graphically, with fps per 100W to make the data more legible:
[ Anno 2070 1080p Max ] [ Battlefield 3 1080p High ]
These graphs highlight the reduction in energy efficiency that results when the TDP is maximised using voltage increases. This yield is a good deal better than what the previous generation provided, but the Radeon HD 7870 and above all the GeForce GTX 670 remain more efficient.
Note however that each game represents a particular case and that the yield varies from one card sample to the next, on the Radeons because their energy consumption varies and the GeForces because their maximum clock and therefore their performance levels vary. Here, the GeForce GTX 680 went up to 1110 MHz and the GeForce GTX 670 up to 1084 MHz.