As of April 2006, there have been five revisions of the MacBook Pro, A-E. Serial numbers of the original begin with W8608.
1. W8608, Rev. A.
2. W8609, Rev. B.
3. W8610, Rev. C.
4. W8611, Rev. D.
5. W8612, Rev. E.
We wonder what went wrong here, as this is a very fast and unusual hardware revision schedule for Apple. The models demonstrated at Macworld Expo were preproduction prototypes, and shipping models have had reports of whining, AirPort problems, flickering displays (esp. at maximum brightness), and excessive heat. Perhaps the combination of Intel designing the motherboard and Apple designing an even slimmer enclosure have both been contributing factors, but these issues should have been worked out before Apple began shipping the MBP, not worked out in the hands of guinea pig customers during the first six weeks or so of sales.