Power Consumption And Noise
We already saw in our Radeon HD 5870 review the effects of ATI’s power-saving efforts on this generation of hardware.
Those results carry over fairly evenly here. As expected, a single Radeon HD 5850 and 5870 idle at roughly the same power levels. And as a load is applied, the lower clocks and disabled sections of the GPU help shave off as much as 49W—even more than the 37W ATI told us to expect. Those savings multiply out when a second card is added, though. A Radeon HD 5850 CrossFire setup uses 92W less than a 5870 CrossFire arrangement under load.
Incidentally, the two 5850s also use less energy than a single Radeon HD 4870 X2, a single GeForce GTX 295, and two GeForce GTX 285s. We’d hesitate to call the Radeon HD 5850 a “green” graphics card, but it is the most energy-efficient high-end board ATI has released since the original Radeon HD 4870.
Here’s something special. While there’s little difference between any of these new 5800-series cards at idle, one Radeon HD 5850 under load is almost as quiet as a Radeon HD 4870, and two under load are quieter than a single Radeon HD 5870 at full tilt.
Perhaps more impressive was the fact that two cards never broke 90 degrees Celsius under load, whereas the Radeon HD 5870s were easily made to throttle at 100 degrees. Cooler, quieter, and more power-friendly. Nice combination.