I am planning to buy a MacBook Air to run Cisco/Juniper router sims for my networking certifications. What am I giving up, in terms of graphics performance, when the MBA's don't have discrete graphics like the MBP's? I'm currently using a 2007 15" MBP C2D, with the Nvidia GPU. I'm thinking of changing to a lighter MBA, so that I can bring it with me on my commutes from home to work and back. I don't play any games at all, but do watch movies on it. Will the current generation MBA be a downgrade in terms of graphics performance compared to my 2007 15" MBP?