Hi!
I stumbled upon this thread in search for a solution to my own "whining" CPU.
I'm extremely sensitive to sound, and this one almost gives me a headache.
It started a few days ago and I was hoping that it would eventually disappear, but I can't stand it any longer so I'm probably going to contact the nearest service place in the next few days. As for this being "normal", the whining wasn't there 6 days ago, and I've had this MacBook for roughly 3 months now.
I can almost say for sure that it's the CPU that's making this noise, not some fan. I used "QuietMBP" on my Alu MacBook 2.4 and when I moved the slider, I could hear a clear difference in the sound when I was moving it back and forth.