I have a MacPro 2.66 quad-core intel. 4gb ram. I have a hard-drive from my old Powermac that i upgraded to 10.5.5 for this computer. Everytime I put my computer to sleep, and then wake it back up. The fans spin up to maximum speed and all the fans are running really loud and then after about a minute all spin to normal speed. I don't have any other flaws except for this. Why could this be?