1.56Gb is not enough for 1920x1080 anymore. I'm constantly coming to a VRAM bottleneck, especially with BF3, Max Payne 3 and Sleeping Dogs. No AA makes me sad.
It's ok with games like CS:GO but big open games with long draw distance and new games it just fails.
Disabled Aero?
Sleeping Dogs used like 1100-1200 for me even with Max AA so definitely not the case for that.