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 quality mode:
The GeForce GTX 670 consumes a good deal less than the GeForce GTX 680, in spite of what you might think from the relatively close specifications of the two cards. In demanding tests its energy consumption is similar to that of the Radeon HD 7870 but it consumes more than the HD 7870 in less demanding tests as GPU Boost maximises use of the available thermal envelope.
AMD retains the advantage in the standby screen thanks to the ZeroCore Power technology
We have shown the energy consumption readings graphically, with fps per 100W to make the data more legible:
[ Anno 2070 1080p Max ] [ Battlefield 3 1080p High ]
Thanks to the 28nm fabrication process and the revised GK104 architecture, the GTX 670 gives a significantly improved energy yield. The GeForce GTX 680 has a slightly better yield than the Radeon HD 7970 in Anno 2070 and is 15% up on it in Battlefield 3 but the Radeon HD 7870 is still the most efficient.
Nvidia has however made a good deal of progress and, without pushing the GK104 to its limit, the efficiency of the GeForce GTX 670 has improved, with a 25% advantage over the Radeon HD 7950 in Anno 2070 and 30% in Battlefield 3.
Note however that each game represents a particular case and that the actual 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 clocked as high as 1110 MHz and the GeForce GTX 670 1084 MHz.