Activity Monitor on the Apple Mac is a useful utility for seeing what is going on under the macOS user interface, but it is too demanding of resources. Here are lightweight alternatives.
Is the CPU busy? Is memory or disk space running short? Which apps are using the most CPU and RAM? Why is a file taking so long to download? Is it the network speed? What is the time remaining on a MacBook’s battery?
There are many questions you might need the answer to when using your Mac and Activity Monitor can answer all of them. You can easily see technical information like CPU, memory, disk, network and even energy (battery) usage.
There is no doubt that Activity Monitor is a great app, but it is not one that you would want to leave running on the desktop all day because it uses system resources and desktop space. On older and less powerful Macs, Activity Monitor uses a lot of CPU, memory and energy. Run it and check the tabs to see for yourself if you have an Intel Mac.
It’s not a problem for the newest M2 powered Macs, but it is noticeable on the original entry level M1 MacBook Air. Resource usage is most noticeable with older Mac that have less powerful Intl CPUs, less memory and ageing batteries than with brand new Macs. If your Mac is a few years old, the demands placed on the system by Activity Monitor and the latest version of macOS are too great to leave it running all the time. It uses screen space too.
On my old Intel MacBook Air, Activity Monitor can use as much as 24% CPU activity. On my M1 MacBook Air it can be 8 or 9% CPU. Its energy usage is also high and this will inevitably cause faster battery drain. I run it, take a quick look at the data and quit as soon as I can.
The two alternatives here use much less CPU, memory and energy and they can be permanently active. They work on new Apple Silicon Macs and older Intel Macs and are free.
Stats menu bar system monitor
Stats is a free and lightweight system monitor for the menu bar on an Apple Mac and is an alternative to Activity Monitor. It shows brief information in the menu bar itself and detailed information when it is clicked.
The menu bar system stats are always there, always visible and do not get in your way, unlike the large Activity Monitor app window on the desktop. If you are wondering whether the CPU is overworked, the memory is running out or the disk is nearly full, you can see it without interrupting what you are doing.
In the app’s settings you can choose what modules to show in the menu bar, and this includes CPU, GPU, RAM, disk, sensors, network, battery and Bluetooth. The developer warns that the sensors and Bluetooth modules require more power than the others and this is just the way that Apple Silicon Macs work. However, if you want to see fan speeds, temperatures and so on, you can enable it.
Each of the menu bar modules has several options and labels can be shown or hidden, colored or monochrome, aligned left, right or centered. The update interval can be selected from 1 to 30 seconds. With just the CPU, RAM, network and battery modules enabled, Stats used hardly any power at all on my M1 Mac. This is great and you can monitor system usage without putting any extra workload on the system.
When each of these is clicked, a panel displays detailed information and this has more configuration options. For example, you can choose the number of items to show using the most CPU or RAM, or set an activation level for network activity so trivial accesses are ignored.
These panels provide a lot of useful information, but you do need a bit of technical knowledge to understand the contents. You don’t need to be an expert to use it, but it helps.
Eul menu bar activity monitor
Eul is an activity monitor for the Mac that enables you monitor the resources the Mac and apps are using. (Get it from the website, not the App Store.) This free app is different to Activity Monitor in several ways and the most obvious is that it runs in the menu bar rather than in its own window.
Start it and several icons and numeric information appears at the top of the screen on the right. For example, it can show the CPU usage as a percentage and the temperature in degrees (Celcius in my case, but probably Fahrenheit in the US). Following the second icon is the memory used and free, memory temperature and percentage used.
There is a fan icon and fan speed, network or internet upload and download speeds, battery percentage and time remaining. This is all very useful information and you can see system stats at a glance. However, there is so much more to see by clicking anywhere in this menu bar display, more than will fit on my MacBook screen.
There are several sections and the first shows CPU usage. There are some basic stats and this is followed by a list of the apps using the most CPU. Look at the screenshot above and notice tat Activity Monitor is 21.4 and eul is 5.2. That is a big difference, but it is often greater as Activity Monitor is frequently 24% to 25%.
A bit further down the panel is the memory usage. There is a summary followed by a list of apps and services using the most memory. Notice that Activity Monitor is 49 MB and that eul is too small to make this list. It uses around 18 MB of memory, which is significantly less.
Eul does not display the full list of running apps and services in either the CPU or memory sections, just the worst offenders. Activity Monitor has more information here, but is it worth it? Eul shows what you need.
See more system information
In some areas, the eul activity monitor shows more information than Apple’s Activity Monitor and here is the battery section of the drop-down menu bar panel. It shows the battery health percentage, maximum and current charge capacities, cycle count, condition and more. It is all important data.
It shows more information in other areas too and you can see the fan speeds and temperatures of components that are not normally visible elsewhere in macOS.
Configure what you want to see
The information that is displayed in the menu bar and in the drop-down panel can be configured. You can choose what to show and anything you are not interested in can be excluded. Here are just a few of the options in the app’s preferences.
The menu bar components can be selected and the order in which they appear can be set. With some items there are several display options and with CPU for example, a mini graph can be included which shows the CPU activity over the last minute or so. The GPU and memory displays can show a similar activity history graph. CPU, GPU and memory can all show the current temperature if you want to keep an eye on whether the Mac is getting too hot.
Summing up
When you need to see everything that is going on in macOS, Activity Monitor is good, but uses too many resources. Stats and Eul perform a similar function using fewer system resources and they don’t have a window taking up desktop space.
They are light enough to keep running all the time and the menu bar information makes it easy to keep an eye on what is happening. These are great free apps for the Mac.
