AMD A8-3870K - Radeon HD 6550D Graphics
Doom 3 era games with the Catalyst driver controlling the Radeon HD 6550D can easily run at playable (60+ FPS) frame-rates with a 1920 x 1080 resolution.
With Unigine Sanctuary, the Radeon HD 6550D graphics are running at less than 50% the speed of the Radeon HD 5750 graphics card but at more than three times faster than the Radeon HD 5450.
Running Unigine Tropics and Unigine Heaven on the APU when overclocked to 3.6GHz ended up being not stable in this particular configuration regardless of the applied voltage levels.