Early last week, my 2011 MacBook Pro started acting up. The fan was spinning wildly and the aluminum case was hot to the touch. So hot that it left red marks where it was resting on my legs and the laptop shut itself down. I fired it back up again, shut down some of the extra apps that usually run in the background and kept working. Things cooled down inside my MBP, so I just brushed it off as an unusual combination of warm weather and excess apps. I was wrong -- the next morning and again the next evening I experienced the same overheating.
To help diagnose the problem, I turned to iStat Menus from Bjango to see what was going on underneath the hood of my Mac. iStat Menus is perfect for diagnosing problems as it tracks a wide variety of statistics for your Mac. The app sits in your menu bar and can track your CPU & GPU usage, memory usage, disk activity, network activity, battery level and sensor readings like temperature.
I picked iStat Menus because it was the first one I found that measured hardware as well as software. I was interested in fan speed, which is measured by iStat and not by built-in tools like Apple's Activity Monitor. My previous laptop overheated due to a bad CPU fan, so I initially thought I was dealing with a hardware problem again. I was able to put CPU die temperature (which once climbed to 99°C before my MBP shut down), CPU proximity temperature and exhaust (fan speed) in my menu bar and monitor them simultaneously. This let me watch the fan speed ramp up as the temperature went up, so I knew something else was awry.
I then watched the CPU usage using iStat Menus and in just a few minutes, I was able to determine it was a software issue. I singled out TweetDeck as the culprit that was maxing out my CPU and driving my temperature upward. As soon as I force quit the Twitter client, I watched my MBP CPU temperature fall back down to a comparatively cool 50°C.
My problems started soon after Tweetdeck was updated on June 14, 2013, but I can't lay the blame on Tweetdeck as I am running OS X Mavericks. I expect wonky behavior like this when I am using beta software. For a few days, I stopped using Tweetdeck and started using it again when OS X Mavericks beta 2 arrived. I am happy to report that this latest build of OS X is Tweetdeck-friendly, and my MBP is now running like a champ again.
iStat Menus is available for US$16 from Bjango's website. There is a free 14-day trial so you can check it out before you buy it.