Hi,
I have uninstalled FCP X, empty the waste basket, shutdown my iMAC. After I started it again and re-installed FCP X it seems now fine. To make a movie in high quality I need now around one hour. Waht I now also see is that the meter (green) in the middle left of the counter, is now showing 100, earlier it was showing a number between 50 and 70.
I hope it is now better.
Fred