Kicking things off with Nexuiz, the Radeon HD 7660D performance on Ubuntu 12.10 in a stock configuration came shy of 60 FPS at 1920 x 1080 but well ahead of the Radeon HD 6560 and NVIDIA GeForce GT 220/240 graphics cards. Some of these results came in close to 30/60 FPS, but as always, the Phoronix Test Suite enforces disabling vsync on the different drivers, so there might be other driver issues at hand if it's just not a coincidence. It will be more interesting to compare the Llano and Trinity graphics performance once those Linux numbers are available at Phoronix.
For the open-source OpenArena 0.8.8 first person shooter, it's a similar case of the HD 7660D coming up short of the Radeon HD 6570 while noticeably ahead of the Radeon HD 5450 and GeForce GT 220/240 graphics cards.
Obviously if you're running some lightweight Linux game like World of Padman, the OpenGL workload is very easy to cope with for the AMD A10 APU.