I just upgraded my 2009 Mac Pro from the NVidia GT120 to an ATI 5770. I have noticed that the PCI exhaust fan idles around 1600-1800 rpm and it is pretty loud for a Mac. I realize that the 5770 is not officially compatible with the 2009 Mac Pro, but it seems to be pretty close. I have noticed that I only have this fan problem after the computer has been shut down. If I restart, the fans are normal. I have tried the SMC reset. Anyone have any other ideas?