Going after another Macbool pro - noticed the engines have undergone some changes in at least name. My older 13 is 2.7GHz dual core 17. The new 5 runs at 2. GHz. So do I get a pretter package with lest GO; or am I misreading the GO? Then there are the new processors waiting in the wings. I now know exactely what how a dog feels chaising the tail.