iStat Menus 4: Menubar System Monitoring, Improved

Sometimes it’s good to know what’s going on beneath the hood of your Mac. Keeping track of memory and processor usage helps you manage open apps and current tasks, ensuring that your computer never grinds to a halt because you’re doing too much at once.

iStat Menus is one of the more popular apps to help you keep tabs on your Mac, with its advanced monitoring of memory usage, processor usage, network bandwidth, hardware temperatures, and much more. It just got a major new version upgrade, with a slew of new features — including history graphs, calendar events, and an improved interface — so we thought we’d take a look to see how this new release stands up.

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Wait: What is iStat Menus?

iStat Menus offers several monitoring systems for checking up on how your Mac’s running. You can see CPU usage, how much free space is on your hard drive, how much RAM is in use, what temperature your hardware components are at, how much data you’re transferring on your network, and much more. The best part is that each of these sits in your menubar, with at-a-glance information that can be expanded at the click of a button. You can have graphs or numbers (or both) for the key data in the menubar, then a breakdown of usage in the drop-down menu.

My menubar, including the iStat Menus, uh… menus for CPU, memory, network bandwidth, sensors, and time/calendar monitoring.

All told, you have eight menus that can be toggled on or off: CPU/GPU, Memory, Disks, Network, Sensors, Battery, Time, and Combined (which combines the individual menus into one). The Time menu serves as a great replacement for Apple’s default menubar clock, with a selectable calendar that shows events (finally) and a world clock (for seeing what time it is in other parts of the world), while the Battery monitor similarly improves upon Apple’s own offering. All of the others tap into information that you’d otherwise have to juggle multiple apps and windows to monitor.

The iStat Menus Preferences, which is oddly not accessible from the menus anymore (but rather must be opened like any other app).

iStat Menus has been around for years now — we first reviewed it back in May 2010, when the third major revision was released. Back then we praised it for its detailed stat-tracking of nearly every all of your computer’s resources, with the added bonus that you could pick and choose just the information that’s important for your menubar. Let’s see what the new version brings to the table.

What’s New?

iStat Menus 4 adds history graphs, more stat-tracking, and a new layout. The changes in design are subtle and of mixed effect — information in the menus, which has been slightly re-ordered and given better contrast, is now clearer and easier to digest, while the Preferences have been streamlined. The app is now more user-friendly on the whole, but there’s strangely no option to bring up the Preferences, Activity Monitor, or Disk Utility direct from a menu.

History graphs for the different monitoring systems give a much better indication of usage over time. For CPU, memory, network activity, and sensors, these graphs come in three flavors: one hour, 24 hours, and seven days. Load averages and disk activity add a fourth graph for the past five minutes. Most of these graphs are hidden from view — only the one hour memory, network activity, and CPU graphs show up when you click on the relevant menu item.

Look at all the graph prettiness. There’s another set of graphs attached to the Uptime section.

To display them, mouse over the relevant information. Most menus hide information within submenus attached to their elements. The Sensors menu has a different set of history graphs for every single component being monitored. There’s an abundance of information available for the curious or obsessed. But it stays out of the way for more at-a-glance style monitoring. This seems like a good compromise — the extra detail you may sometimes want is there, but you won’t notice it unless you go looking. (And really, does anyone obsessively monitor graphs of the same information over time scales? Surely one graph is enough 90% of the time?)

I love the new color-coded memory usage graph. All it’s doing right now, however, is reminding me that I need more RAM.

The few days I’ve been using iStat Menus 4 haven’t given me enough data yet to see any reliable patterns or trends, but these history graphs should be a great helper in keeping my computer running smoothly and diagnosing unusual activity.

Doubly so in the case of network activity, since the new version adds per-process bandwidth monitoring. The five most recent processes to transfer data on the network show up at the bottom of the Network menu, with their current transfer speed displayed alongside the process name. Unfortunately it doesn’t offer tracking of total usage per process, or display upload transfer rates — either in the current session or long-term. Little Snitch is still the king of serious network monitoring, but this is great aid to doing quick checks of at-this-very-moment bandwidth usage. If there’s significantly more network activity than you expect, you’ve now got a good chance of identifying the culprit with a glance at iStat Menus.

You can see per-process network traffic for the five most recent apps to send or receive data, but it’s not tracked long-term like other data and it’s never clear whether you’re seeing upstream or downstream information.

GPU monitoring was added in the 3.16 update, but it consisted of just a bar indicating VRAM usage. There’s now also a frames-per-second counter, which is sure to please (or displease, as the case may be) the nerdy among you. There’s no graph to go with this one, however.

Sensing a Change

As before, you can set up rules that dictate the minimum speed your fans spin at in different scenarios. You still can’t automate this according to the temperature of a component, however. The addition of history graphs for each component negate this somewhat by enabling you to fine-tune your settings. If your CPU is running consistently hot, you’ll see it clearly on the 24-hour and 7-day history graphs, and then you can adjust your rules accordingly.

The Sensors menu is still a bit buggy — those fan-speed sliders are not in the right place according to my “Medium” settings. Note that every single item in this menu has a set of three history graphs associated with it.

With this new version of iStat Menus, it’s easier than ever before to notice anything untoward with your computer. But, as before, you’ll only be able to use it for monitoring — it’s an aide in any diagnoses of problems, and a great help in lots of little inconsequential things, nothing more. Mostly it’s useful for battery monitoring, checking the time elsewhere in the world, and quickly looking at your calendar — the other monitors are nice to have, but hardly important to the majority of users’ workflow.

The improved calendar rocks, and now serves as one of the better menubar calendars going around.

Should You Upgrade?

It’s easy to get lost in the excitement of new bells and whistles without thinking about whether you need them, and in this case it comes down to your use cases. If the graphs don’t excite you, there are probably just three things to consider: The new Time menu, per-process network monitoring, and Retina graphics (which it has, by the way).

The changes to the Time/Calendar menu make iStat Menus one of the best menubar calendars around, while the per-process network monitoring — as rudimentary as it is — offers quick and useful insights into data transfer rates as they happen. iStat Menus 4 is the same menubar monitoring app I’ve come to know and love, made better — with more features, an improved layout, and further integration into the Mountain Lion ecosystem. But if you don’t need history graphs, the price of an upgrade may be a little too steep at this stage.


iStat Menus 4 makes an already-great app better with an improved design, history graphs, Retina support, per-process monitoring, and calendar events. It's fantastic for keeping you on top of CPU/memory usage, disk space, battery life, network traffic, and more, right from your menubar.