So one of my ex students turned up at King's College with a Mac and an iPhone and wants me to carry on teaching him online so I immediately thought of iChat. Then all of a sudden I discover it's been abolished by Mountain Lion so I thought of upgrading from L to ML and using iMessage and FaceTime.

Does anyone know if there'd be any speed penalties going to ML an old iMac running 3.33 GHz Intel Core 2 Duo with RAM maxed out at 16 GB? I run Parallels quite a lot for trading on a Windows-only app so that's another worry if anyone knows of any issues with that. Many thanks,