hi i have g4 mdd that i replaced the logic board and cpu in . i bought new memory but it was 2700 instead of 2100 .doesnt seem to reconize this ram . has anyone had this problem before ? i is really messing with my mind . im not sure if this ram brand is backwords compatible or not . i get a long beep after i start it up which is supose to be no ram found but i have 2 512 sticks pc2700 in the board . any sugestions ????? Bryon