I know that it might sound a little odd but are you sure u were writing at 48%. I say that because if you were, the cd should be written in one minute or less. If you were burning in 2 min then u were writing at 40 or 32 or even less. So there is no problem. The thing that changed is that
nero now shows the actual writing speed. otherwise check your ide configuration or an older version of nero. good luck