Hi I am considering investing in a new PC which I'll be using Sage ( and R under Sage ) a lot and will be doing computations that will be intensive at times. I am considering either Mac Snow Leopard with a new quadcore MacBook or the latest Ubuntu running on a partition on a quad core Windows 7 machine. I would like to know what differences there might be running Sage on these two platforms, with special interest toward performance. I'm just getting involved with Sage but have to make a decision about hardware and OS very soon. Any info would be much appreciated. Doug