Nice write up, thanks for helping defuse this latest myth.
I do have a couple of points. While unimportant to your experiment two ways to actually crank up the heat on the CPU better than the yes >/dev/null are:
echo 'scale=10000;4*a(1);' |bc -l -q
This calculates Pi to 10,000 digits. Either run with an & and up arrow to run again on a second thread or with two Terminal windows.
The other is to use the openssl speed function. This reportedly stresses the CPU pretty well and is easier to type:
openssl speed &
The other point was you can get a real reading on the CPU temperature with a kernel extension written by InCrew.org:
You can find it nicely packaged version called CoreDuoTemp. It with a GUI application to measure temperatures and the current SpeedStep CPU frequency here:
Thanks again for this. It is not something I was willing to do with my MacBook Pro but I was curious to find out if there really was something wrong with Apple's build process. I'm pretty now confident that there really isn't.