System Monitor: Tom's Mac Software Pick

System Monitor with General preferences displayed.
Screen shot courtesy of Coyote Moon, Inc.

Do you enjoy tweaking your Mac, trying to get maximum performance out of its hardware? Or perhaps you're having some type of intermittent problem that you think may be related to your Mac’s internal temperature, or other stress factors your Mac is under.

There are quite a few system monitor apps available for the Mac, including some like Activity Monitor, which is supplied free with the Mac. For those power users looking for monitoring tools, Marcel Bresink’s System Monitor is hard to beat.


  • System Monitor is displayed as a menu bar, keeping it always available and out of the way.
  • Customizable display.
  • Seven key components monitored, each with a vast array of monitoring options.


  • Crowded display in menu bar.
  • Mostly a black-and-white display; limited use of color for organization.
  • No alerts or warning capabilities.

System Monitor is an app that monitors key components of your Mac and displays their activity in near real-time in the Mac’s menu bar. There are seven components that are monitored:

  • Processors
  • Main Sensors (CPU temperature and fan speeds)
  • Memory
  • Volumes
  • Disks
  • Network Interfaces
  • Activities

Each item that is monitored offers various options, from disabling the monitoring of the item, to defining parameters for how the monitoring is performed. While configuring each item can be done easily enough, to fully understand the configuration options, you'll need to make a trip to the help file and the included manual.

Using System Monitor

System Monitor installs as an app located in your Applications folder. It actually can be stored anywhere you wish, but the Applications folder is as good a spot as any and ensures it will be detected and updated via the Mac App Store.

While the most visual part of the app is the long sequence of icons and data added to your Mac’s menu bar, the actual interface to set up the app is its preferences, which allow you to configure each of the seven monitoring areas.

General and Menu Bar Layout Preferences

Preferences are broken down into the seven monitored items, plus a preference for general settings that apply across the board and a setting to control the menu bar layout. In the Menu Bar Layout, you can control the size of the history and bar graphs that are displayed, as well as the order in which the monitored items are shown.

The General Settings allow you to specify the temperature scale to use, how memory size is displayed, and if the public facing IP (the WAN side of your network) should be displayed. There's also a slight hiccup in the app at this point. If you choose to display the WAN address in the Network Interfaces, the app assumes you're using a dynamic DNS service and requires you to provide information about the service you're using, and how often to force the WAN address to update.

Information Source Settings

The seven monitored items each have their own preference settings, allowing you to customize how data is collected and displayed for each item. In most cases, you have the choice to use various chart types, actual values, or percentages, as appropriate for each item.

Some of the more interesting settings include those for disks, which can monitor, read, and write throughput, peak or write speed, total read or write operations, and quite a few more parameters that can be important both for monitoring performance of your disks, and also for predicting possible failure modes that may be getting ready to occur.

Another interesting setting is for Activities, which harkens back to the days when most Macs used external drives, each having its own access light that lit up when a read or write occur. If you miss the days of flickering computer lights, you can use the Activities monitor to watch for any use of a disk or network interface, and display the results as activity lights in the menu bar. Be prepared for a lot of blinking lights.

The rest of the monitored items are easy enough to configure, but if you have any questions about them, System Monitor has a pretty good help system that includes a write-up on how to configure each item, nicely explaining what each option does and how to use it.

The System Monitor Menu Bar

Once everything is configured, you can go about your daily work and look up at the menu bar from time to time to see how your Mac is performing. Of course, the real use for System Monitor comes when you're experiencing an issue with your Mac, such as a beach ball/pinwheel cursor, slow networking, or other bits of computer aggravation. With System Monitor active, just a quick glance can help you understand what's going on, and, hopefully, help you solve the problem.

Final Thoughts

System Monitor is a fantastic model; putting the system monitor in the menu bar was a great idea. The problem with many other hardware monitoring apps is they take up quite a bit of screen real estate, making them less effective as you have to move windows around to see them when you're actually working on your Mac, as opposed to just watching the monitoring app. System Monitor lets you get back to work and easily ignore the monitoring, except when something questionable happens, and then the information is right there in the menu bar.

The downside is that the menu bar can become very crowded with all of the System Monitor options turned on. To get the most out of the app, you need to be careful, and just enable the functions you think you're going to need; that will help keep the clutter down.

The black and white display is rather dull and a bit depressing. A touch of color would do wonders, and help with visual organization between the various items that can be monitored. When the items are all black and white, they tend to just run together, making it harder than it needs to be to pick out a specific item.

Nit-picking aside, System Monitor does exactly what you'd expect it to do, and it does it by using the menu bar and not by taking up screen real estate you need to get your work done. If you would like to keep track of your Mac’s performance or have a problem that could be helped by monitoring various hardware items, System Monitor deserves a look.

System Monitor is $4.99 and is available from the Mac App Store. A demo is also available from the publisher's website.