So I got a new Late 08 MBP 2.8 earlier this week. Everything has been great except that occasionally (once or twice an hour) my laptop screen will go black for about 200-300ms and then come back. Often only the top 1/2 or top 3/4 of the screen will go black. I was worried it was the LCD, but today I switched over to the 9600gt for the first time and the problem seems to have gone away. I generally code all day and havent been doing anything intense when the flickers happen, the CPU/GPU temps are also low. I have an external monitor hooked up. Ive only noticed the problem when the external monitor was hooked up but then again 90% of the time I use the computer it has the external plugged in. Anyone else notice this? Also does anyone know if the 9400m's 256mb of memory is shared with the main RAM, ie if I am running on the 9400 do I only have access to about 3.74 gigs of ram?