I detected a very strange temperature behavior on my MacBook Pro. I rebooted the notebook after updating to OS X 10.4.7. Then I started browsing the net (reading up on this forum, mostly) when I noticed that the CPU temperature as reported by CoreDuo Temp was at 62±2°C. This is very unusual since I have never seen the temperature this high before. For the next 5 minutes during which the computer remained idle, I observed that the CPU temperature remained at 62±2°C. Then I let the computer go to sleep for about 60 seconds. Upon waking up, I found the core temperature to be 51°C. For the next five minutes, I observed the temperature, again. It remained unchanged at 51±1°C during which the computer remained idle. Then I let the notebook go to sleep for the next five minutes. It should be noted that the ambient temperature at this time was about 70°F (21°C). At the end of five minutes, I awoke the computer and found that the CPU temperature was now reading 29-32°C. Even with light web browsing, the core temperature remained unchanged. I repeated the test above with iStat Nano to obtain almost identical result, confirming that the anomalous thermal behavior is not due to a glitch in the temperature monitoring program. Reason for the abnormally high idle temperature in the 60s is not known but now I know how to bring it down quickly. Just let the computer go to sleep for at least 5 minutes and resume use. Perhaps someone with a good understanding of MacBook Pro architecture can explain this unusual thermal behavior.