I'm using a 2010 Mac Pro with FCP and I've imported a .m4v file (6 mins, 36.5 K/Sec, MPEG-4, 1024x768). When I put it in the timeline and then increase the speed or something so it requires rendering it is saying it will take 3 hours with a message saying "Writing video...". Surely I must be doing something wrong but I'm new to FCP so I don't know what. Any ideas? Another thing worrying me is in FCP "System Settings" it is saying the maximum memory is 2560mb even though I have 6gb.