Radeon Driver Power Management Has Room For Improvement
Looking at the system power consumption for the different hardware and driver configurations is quite interesting. The lowest power consuming configuration is the open-source driver with the low-power mode, but that is expected. The Catalyst driver and the open-source "DynPM" mode are dynamically adjusting their clock frequencies based upon need, which for the OpenArena workload means running in a higher power state.
Using the dynamic power management mode had saved around 2 Watts for the Radeon HD 5750 and 13 Watts for the Radeon HD 4870.
When comparing the default open-source Radeon driver configuration to the Catalyst driver, AMD's proprietary driver is far more efficient. Not only does the Catalyst driver deliver better performance, but also its power consumption is lower. With the Radeon HD 5750 its power consumption rate was better by 10 Watts over the default Radeon driver, 36 Watts for the Radeon HD 4870, and 15 Watts for the Radeon HD 4550.