I received the new revision of the Main Logic Board also on my 1.83 MBP. The computer was sent in due to the cpu whine. The computer came back with a wiped HDD, freshly installed with 10.4.6 and a new set of DVD installation Media. The whine is almost nonexistant now. I can't hear it unless it is dead silent and I put my head against the keyboard. Previously, it was very noise and distracting, even in a somewhat noisy environment. I have also noticed that the temperature of the MPB is considerably less. It runs now under normal usage around 45C as compared to 63C of my old one. I am very satisfied with the service that Apple has provided in replacing the logic board.