During the installation process, optical drive trays will be opened and closed, so pay attention.
A Mac Pro SMC Firmware Update is also available from apple download website:
http://www.apple.com/support/downloads/macprosmcfirmwareupda
te.html
You will need it only if the SMC version of your MacPro is earlier than 1.7f8. Recently shipped Mac Pro have a 1.7f8 SMC version. It adjusts fan behavior in the Mac Pro
