I used to get quite bad performance on nfs mw when using windows 7, specially when turning visual treatment to high. The best way I've seen that works is by using the Graphics Optimizer tool Angelic spoke about, disabling motion blur, and suddenly the low visual treatment settings have the same look as the regular high settings, without that gloomy blue tint over the screen, and nice performance when running at 800x600 with near minimum settings.
-- 9xx SOLDIERS SANS FRONTIERS
