I have recently replaced logic board on my MBP 3,1 to REV 2 version。 Ever since the replacement my MBP is giving random but strangely software related problems. One of the most prominent problem is screen blackening on certain programs(program that has lots of text and scrolling, eg. safari, contacts etc.). This seems to be triggered by connecting external monitor. Also it seems to be happening more often and often. Other problem includes excruciatingly slow TimeMachine performance... it took me 3days to back up 118GB worth through gigabit ethernet.... it used to take 10hrs max... So my question is this software problem or hardware? And even is it worth taking to Genius?