Power, thermals and acoustics
It took a while for AMD's partners to fashion dual-HD 7970 cards. One reason for this must rest with the comparatively high power-draw of top-end Radeons. Club3D's effort, whilst overtly massive, uses two relatively energy-efficient GPUs; their combined power consumption is comfortably below that of two discrete boards. AMD's ZeroCore technology drops the idle power consumption down to 50W when in long-idle mode.
That massive cooler provides excellent thermals, keeping the two GPUs well below 80°C under extreme gaming load.
But the compromise for excellent temperatures is a card that can be very noisy. It is significantly louder than a GeForce GTX 690, more so than the logarithmic decibel figures suggest, and we'd like to see the card pre-programmed for higher temperatures at the expense of some noise.