Freeware of the Day: atMonitor for OS X

atMonitor is Peter Galvin’s go-to favorite freeware tool for getting a quick snapshot of the state of his Mac systems.

Here’s  my choice for freeware of the day. It’s atMonitor. It’s my favorite freeware — actually, it’s donationware if you want to be strict about it. This tool lets me get a quick and deep view of the state of my Mac systems. The atMonitor tool displays vital statistics in the menu bar in Mac OS X. It shows CPU and GPU loads, memory and virtual memory use, disk and network I/O, CPU and GPU temperatures and even frames-per-second (FPS) graphics performance.

I run it on all my Mac OS systems.

I use it to check to see if Firefox is yet again using up too much CPU — or to check if some application is using my network.

If my system is sluggish, this is my first tool I use to get a handle on where the problem lies. Beyond performance, atMonitor also gives you detail on system configuration such as current IP addresses and active processes. That’s useful. Check out advanced features like Purge Memory.

atMonitor is highly customizable. Display information in a floating window or the menu bar, select specific aspects of the system to examine and fine tune the presentation of information for each component.

I have used atMonitor for a while and I haven’t noticed it draining system resources or depleting my laptop’s battery. I highly recommend it for any Mac user who is curious about what their system is up to.

About the author

Peter Baer Galvin

Peter Baer Galvin is CTO for Corporate Technologies, a premier systems integrator and VAR ( Previously, Peter was the systems manager for Brown University¹s Computer Science Department. He has written articles and columns for many publications and is co-author of the Operating Systems Concepts textbooks. As a consultant and trainer, Peter teaches tutorials and gives talks on security and system administration worldwide. Peter is also a Lecturer at Boston University and a Senior Contributor to BYTE and Peter blogs at and tweets as @PeterGalvin.

  • Pretty neat stuff

    -RAP, II

  • Rob Maxwell

    So I’ve always used iStat products for the same jobs. Recently I’ve been having stability issues with a MBP and contacted iStat’s owner to find out if I could pipe the temp data to a log of some sort to see if the stability problem correlated in any way with cooling issues.

    Their answer? “you can’t do that.”


    I’d have been cool with we haven’t tried it before, or we don’t know how to do that. But can’t?

    So, will atMonitor let me do this?


  • Peter Galvin

    Hi Rob, I used to use istat as well and found it to cause problems in my system.

  • mpod

    I don’t see where atMonitor measures virtual memory… VRAM is Video Ram, no?