I am in the process of testing EB on both BI and Alexander. I read in several posts that both improve AI, stability and speed. Honestly though, I think that 1-2 minutes between turns is ok. I have been playing using my laptop in the office and it takes me around 3-4 minutes between turns. Considering that it can take me 10 minutes or longer to micromanage my empire depending on its size, anything below 5 should be playable. Just learn to relax or do something else in the background. :P