Temps and power consumption
The increase in temperatures is down to two factors. Firstly, having two hot-running cards in one system is never a good thing. Secondly, putting the two cards in such close proximity to one another does little for thermals. The quoted temperature is the average for both GPUs in the system.
Power-draw
AMD's Radeon 5000- and 6000-series GPUs have done well with respect to power consumption. But you probably want to see the power-draw when the system is under the cosh.
The Radeon HD 6970 gets close to the GeForce GTX 580 GPU in most areas. One area that it would rather this not be the case lies with under-load power-draw. The graph tells a different story, showing us that the Cayman GPU is very thirsty. In fact, it's surprising to see the pair consume an additional 174W over the twin-GPU Radeon HD 5970 2GB card.
We're now intrigued to see what steps AMD will have to take when releasing the twin-GPU-on-one-card Radeon HD 6990 - codenamed Antilles.
Eagle-eyed readers will notice that we have excluded the FurMark tests here. The reason for doing so revolves around how both AMD and NVIDIA limit the power coming into their high-end GPUs when an 'out-of-spec' application is run. This limiting causes the Cayman and Fermi v2 results to be inconsistent with all the others.
