The Current State Of Radeon Power Management
The open-source "DynPM" mode was commonly operating at the highest 800MHz state, but at times dropped to 500MHz. The Catalyst driver was also similar but more aggressive and managed to hit some 250MHz steps.
The GPU temperature is also in line with expectations and similar to the results from the earlier tests.
For kicks, here is a look at the GPU temperature in the different configurations for the entire duration of testing from idling through video playback and running multiple OpenGL benchmarks via the Phoronix Test Suite.