I have the GTX 260m and when i play games like Crysis, Crysis 2, or Dragon age (1 and 2) The screen occasionally flashes black and the FPS drops dramatically, but then after a while, it flashes black again and the game picks up and runs beautifully. Does anyone know what may be causing this?
Sounds like your laptop's graphics card might be throttling itself due to excessive heat build up. Try running HWMonitor in the background and see what the maximum temps are for your video card. If the temps are getting too high, you may have to turn some settings down to reduce stress on your GPU, or look at some better cooling solutions.
EDIT: Also check your CPU temperatures, if they are too high the CPU will throttle itself and that would also severely reduce framerates.