Hi, I am buying a new macbook for work. The computer will do some heavy calculations, so I need a strong cpu but also would like a good battery life time. I was looking at a Air at first, but I am unsure how big the performance difference is between the 1.8 GHz of the Air, and the faster 2.7GHz for the Pro. I will have a 256gb SSD drive in both these configurations, and HD3000. So the performance difference should mainly be on the CPU. So can anyone give me specifics, I have tried searching for a good comparison between the CPUs, or Air and Pro's both with SSD drives, but have come up with nothing so far. What I mainly want to know if the higher price of the Pro (~300 euro) is worth it from the (significant?) increase in performance.