I am not too "in" on the computer stuff, but I have a MacBook with a 2.0 Ghz and it is really fast. I know Apple and they would not put out a product (for that price) that was not top of the line and not fast! You will be happy with this product. For question 2....all you have to do is go into iTunes, go to file, and click on Back Up To Disk (or it might be Create Back Up Disk on your PC). Then, it will ask you if you want to back up your entire library or just your recent iTunes Store purchases. Of course click entire library and it will put your entire library on multiple disks. Then, with the MacBook Air, I am guessing you would have to sync the 2 computers together and have it transfer the disks on your PC to the MBA! I hope this answers your questions!!!!! 🙂