Well, I noticed that when running Firefox on my MacBook Pro, my computer runs hotter than it does when I run Safari.

As you can see from the screenshot, the temperature while running Firefox 3 was 138 degrees (temperature in the menubar courtesy of iStat menus, by the way). Actually, the temperature fluctuates between about 133 and 142 degrees. This is pretty hot for a laptop er, notebook, especially when it’s setting on your lap.

In this screenshot, taken about 35 minutes after quitting Firefox and resuming normal browsing with Safari, you can see that my MBP has cooled down by about 14 degrees to a more comfortable 124 degrees.

While Firefox is making my MBP hotter, I’m still using it – for now. The hottest my MBP ever got was a few weeks ago when it reached a scorching 180 degrees. It literally almost burned to the touch. My Activity Monitor reported that a printing process was using over 100% of my CPU. I had no idea that was even possible. Evidently, I had tried (and failed) to print some online coupon that required me to install some kind of silly software just so I could print the thing, and it hung up and caused a serious overheating problem. Fortunately, I was able to kill the process from within the Activity Monitor and return to more human temperatures. Good times.