The Radeons have a unique capability called ZeroCore power that allows them to spin down all of their fans and drop into a very low-power state whenever the display goes into power-save mode. That's why they tend to draw less power with the display off.
Please note that our load test isn't an absolute peak scenario. Instead, we have the cards running a real game, Skyrim, in order to show us power draw with a more typical workload.
The 290X's power draw under load is... considerable at roughly 40W more than the GTX 780. The card's cooler will have more heat to expel as a result.
Noise levels and GPU temperatures
Remember that 95°C PowerTune limit? Yeah, the 290X runs right up against it with either fan profile. AMD calls the card's default fan profile "quiet" mode and the more aggressive 55% profile "uber" mode. You can see why I've resisted calling the default profile "quiet." The 290X ain't exactly that.
Switching the fan to uber mode pushes the 290X past 50 dBA, which is somewhere near my personal threshold of true annoyance. Premium graphics cards have been making strides toward good acoustic citizenship in recent years, and we lauded the Radeon HD 7990 for furthering that trend. The 290X sadly loses ground on this front. Yes, it's possible the tweak PowerTune with a lower fan speed threshold, but you're sure to lose performance if you do so.
As for the 290X's penchant for blowtorch-like temperatures, well, AMD has definitely chosen a more aggressive tuning point than the 80°C GPU Boost target on the GTX 780 and Titan. All things considered, I'd rather not lose my fingerprints when going to swap out a video card. However, I can't bring myself to fret over GPU temperatures of 95° too much, since Nvidia chose the same target for the GTX 480 several years back. Heck, even the old GeForce 8800 GTX ran relatively hot, and I think some of those are still going strong to this day.
What AMD has done, though, is squeeze all of the thermal headroom out of this card. Don't expect much overclocking success on a 290X with the stock cooler.