I have really studied my stats on this issues very closely. And there is no doubt about it. The more tables I play the more my profit per hand goes down. I find when I am playing more than 3 tables at once it starts to become a mechanical game. And I miss out on pots I should be winning. Mistakes you make in NL can take a long time to recover. So for my game I have cut down on the amount of tables I play. 3 Seems to be a good number for me. 2nl and 1 fixed. And believe my I know the deal I have dual screens and the whole setup. But I just think your game starts to suffer when you play to many tables.