Idle and Multi-Monitor Loads
The Radeon R9 290X’s power consumption at idle is surprisingly high. Even though AMD makes a point of highlighting its ZeroCore Power feature, which does drop the card to a miserly 5 to 6 W, you only enjoy the benefit of this when your monitor is in suspend mode. As soon as the desktop becomes active, power consumption jumps to 20 W with one monitor connected. Connect two and you’re looking at 57 W. Three monitors take you all the way up to 59 W. This means that the R9 290X consumes more power than two overclocked GeForce GTX 780s in SLI with more than one monitor attached.
Hardware Accelerated Video Output
During Blu-ray playback (or other accelerated video work), AMD's Radeon R9 290X consumes 70 W. This is bizarre, since the Radeon R7 240 does the same thing under 17 W. AMD clearly has some driver work to do still.
Onwards and Upwards: Gaming
After that negative attention, PowerTune kicks in to do the job it's supposed to do. The technology makes its adjustments so quickly that it's difficult to express average power consumption using one number. There's a lot of variation, and the reading changes based on several factors.
Because we can't be as objective as we'd want, we're providing a range instead. To achieve this, we left the power limit alone in CCC and lowered the board's target temperature to 70 degrees Celsius. The resulting cooling performance is about on par with what AMD’s partners offer on existing cards in the same thermal class, giving us a preview of what they might achieve with their own cooling solutions and R9 290X.
Power figures between 185 and 218 W are pretty darned good in the ultra-high-end segment. In light of these results, I think we can forgive the idle numbers we recorded earlier.
When Push Comes to Shove: The Peak Values
If you want to take the Radeon R9 290X to its limits, then you need to push it hard by increasing its power limit and dropping the target temperature. Under those conditions, it's possible to exceed 300 W. We even saw 335 W from the card, though that's probably not at all something you want to reproduce.
The 225 W we measured using a compute-heavy load and stock settings can be pushed as high as 295 W by giving the fan more room to spin up and targeting a lower thermal ceiling. Unfortunately, those conditions don't last. Once the Radeon R9 290X hits its target temperature, power consumption drops considerably. This explains the card’s relatively low performance in our GPGPU benchmarks.