I bought a penryn 2.5 the week they came out, and have a a very mixed experience since, with a few problems that I was hoping the greater macrumors community could shed some light on. 1. Flashing keyboard backlight/display brightness. - This is the most frustrating one of all. - It makes working in a dark room unbearable. The keyboard backlight and the display brightness pulse under low light conditions, changing from almost full brightness to very dim in a consistent frequency of about once per second. It is like surfing the web in a rave. -It seems as if there is interference with the sensors and the display itself- 2. Choppy HD video playback. - I have an episode of planet earth (.mkv, 4.4gigs for 1 hour) that can't play without getting error messages in VLC. 3. Weird flashing updating of many programs: - White boxes flash over new areas when I scroll to them in many programs, they go away when I stop scrolling, however often leaving things drawn over each other, which dont look normal again until I resize a window or otherwise prompt a refresh. Happens most often in ShakesPeer and Safari. Also youtube videos flash these boxes on their own. Honestly the second two are nit picky and all I really care about it the first one. My sample size is pretty small for HD playback so I can't rule out that my test file is bad. your help is needed and appreciated.