Tracking down the source of my overheating MacBook

My home office is a warm place. I don’t have a thermometer in here, but there is a fair amount of IT kicking out a fair amount of heat. Even so, there are two machines that make a noticeable difference – the Fujitsu-Siemens Lifebook S7210 that I use for work, and my Apple MacBook – both of which have 2.2GHz Intel Core2Duo CPUs (T7500 “Merom”) and 4GB of RAM. Admittedly, the MacBook has also been upgraded with a 320GB disk but Apple now offers a similar, if not identical, option in its current MacBook White model.

It’s quite normal to hear the fan blowing on the MacBook, and iStat Menus regularly suggests temperatures of 50-60°C, but last weekend it seemed the fan was running almost non-stop, and I saw reported CPU temperatures in the high 80s (even peaking at 90°C). After shutting down many applications to reduce the load on the system (iTunes, Photoshop and Bridge CS3, VMware Fusion) and ejecting my external hard disk, it still wasn’t coming down, so I began to have a look around on the ‘net.

The best advice I found was on a Mac Rumors forum post which suggest running up Activity Monitor to see which process was driving up the CPU utilisation (and therefore making the machine run hot)… sure enough, it was a Norton AntiVirus process!

It may have been co-incidence that the product doing this was one which has such a bad name as a resource hog (I’m told the 2009 products are not as resource hungry as their predecessors but this is Norton AntiVirus 11 for Mac, which, according to the copyright notice, dates back to 2007). Whatever the cause, killing that process dropped the CPU utilisation and within seconds the machine was back down to a more normal level.

4 thoughts on “Tracking down the source of my overheating MacBook


  1. helpsvc.exe in WinXP sometimes does that, but I’m not sure why. Over time, I’ve just made it a habit to keep Windows Task Manager minimized so I can see if my processor starts getting slammed when I’m not expecting it to.

    The truth is, it’s more difficult to see it when you have two or more cores. Spiraling processes like that will likely go unnoticed when computers start shipping with 8, 16, or more cores.


  2. @Bill – it’s a sad fact that, as we have more compute power available, we use it less efficiently!

    @Kevin – I didn’t replace it… it’s still running (although Symantec have sent me a new version to review…). Is there a version of AVG for the Mac? (I’m using AVG on some of my Windows machines).


  3. My macbook was overheating, discovered on the net that it was due to an item left in the print cue. The printer software wasn’t even running in the dock, but checking the system preferences showed it up and my fan immediately stopped upon deletion of the print queue.

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