So i recently did a build with an AMD A8-6600k APU for light gaming and CAD use but I have found its laggy even on medium settings in far cry 3 (all medium settings, high 20s low 30 FPS). I don't game much but I did expect more from the APU. I'm considering adding an HD 6670 card as they are only like ~$60, but 1. I'm not sure if 1gb of DDR5 or 2gb of DDR3 is better, and 2. If it will give enough boost over the APU to perform better in games like far cry.