I've got a late-2008 MBP 15" (2.4 ghz C2D, 9600M) attached to another monitor. I generally run both monitors for work. My gaming experience is limited, but I am having a hard time running L4D2 without turning all settings to low. 2 questions: 1 - Would closing the laptop and running only the external monitor be better (or would the laptop screen be better)? 2 - What settings can I reasonably expect to run on this computer?