Under load the GPU temperature hits 81 degrees Celsius. We got the exact same results with a reference GTX 780 card, but bear in mind that the Phantom GLH ships with a 117MHz GPU overclock, while the memory is overclocked by 50MHz. It is obvious that the Phantom cooler does a better job than the reference one. In idle we measured 31 degrees Celsius.
We were particularly impressed by the noise levels. The fans were nearly silent even under load, and of course while idling the card is completely silent.
In terms of power efficiency, we can report that the GTX 780 Phantom GLH can draw slightly more juice than the reference GTX 780. This is quite normal for one factory overclocked card. Overall, performance-per-watt is still good and it is on a par with the GTX 680.