I agree with Gargoylelib!
I don't think that Fair Isle knitting is fast knitting. If you settle in your mind that every 2 rows you will have to straighten your yarns, you'll feel less frustration.
BTW, when you get to the end of row 1, turn the work, let's say clockwise. When you get to the end of row 2, turn the work counterclockwise.
I remember that as being a good preventative to the tangles!
By turning the work first one way then the other way you are, in effect, untwisting them as you go.