The CD player copies audio CDs at 4X speed. Therefore, a full 80 minute CD will take about 20 minutes to copy.
Also, you don't have to listen to the CD while it is copying. You can listen to AM/FM radio, XM radio or even use the HDD. Note though that using the HDD will be very slow when you a copying a CD as it is in the midst of updating itself. You'll see the small recording symbol on the top of the screen (even if you are in navigation mode) indicating that you are copying a CD to the HDD.