Is your Mac running very hot (burning your lap, short battery time, fan on and noisy)?

Janet Carr

14 years ago

While there are a number of reasons that your Mac can be heating up, including some scary hardware problems – like a failing power supply – – that would mean you need to take it in for repair ASAP – it’s more likely that you have a wedged process that is causing the CPU to run full-tilt and heat up. Yup, it’s like your brain: if you use it a lot, your computer gets a bit of a headache. 🙂

It’s not easy to find, but Apple actually includes a utility with Mac OS X that lets you find out if you have a runaway process of this nature. I think that’s a good place to start!

The app is called “Activity Monitor” and you can find it in Applications –> Utilities. Launch it and you’ll see something like this:

You can see what processes you have running, what’s touching your disk (another possible cause of overheating, btw: a process that’s thrashing the disk (really, that’s the tech term for it) and causing the drive to heat up), and lots of other interesting information about how your computer is doing.

If you’re having problems with insufficient memory, you can also see what apps are eating up your RAM too. Notice in this screen shot that Chromium (Google’s developer version of Chrome) is using 192MB of RAM, along with its helper apps that are eating up another 100MB or more. Fortunately I have 4GB of RAM so there’s plenty of space (you can check how much RAM you have by choosing “About This Mac” from the Apple menu, btw).

We’re interested in CPU usage, however, so notice on the column headings there’s one that says “% CPU”. Click on it and if you now see those apps that have 0.0 on top, click on it again to change the sorting order.

Now you should see something like this:

Watch it for a few minutes. If you have an app that consistently is at 90% or more (as I have here with GrowlHelperApp) then you need to quit this application and see if it helps your computer cool off and slow down. To do that, click on the name of the app, then click on the red “Quit Process” stop sign icon on the top.

You’ll be asked:

Your two choices are “Quit” or “Force Quit”. Do the former. If it doesn’t work, then do a force quit. The difference is that a regular “quit” lets the application shut down gracefully, saving state files, deleting any temporary or scratch data, etc. A force quit is the operating system ripping the virtual heart out of the app without mercy. Yeah, it’s brutal and you should only use it as a last resort (unless you’re a fan of that sort of thing).

I’m betting that your computer will cool off and you’ll be relieved not to have a hardware problem.

Now, the question is: why is the app running out of control? Sometimes it’s just a random occurrence and it won’t happen again for months, if ever. In other cases, something’s changed and the app has become unstable for some reason, as is the case with Growl on my Mac. In that case, make sure you have the very latest version of the software, and if it’s still a problem, drop an email to the developer letting them know what you’re seeing and check to see if they have any suggestions.

Good luck, I hope that helps your MacBook heat problem as it did mine. Thank you Dave!

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