In my last Tech Tails article we explored what RAM (physical memory) is, the different categories of memory in macOS, how they are used by the OS and its importance to system performance. I wanted to discuss this topic because at one time or another we have all experienced performance issues with our Mac computers. You may have seen that beautiful colored spinning beach ball or applications have taken longer to launch or your whole system has taken much longer to boot up. These can all be very frustrating telltale signs that something is going on. These can all be resolvable and freeing up memory should be one of the first things you should try before anything else.
Now, I bet you are asking yourself: “How can I see what is using up all my memory?” Let’s take a look, as this is a great question and macOS makes easy for us to investigate and manage memory resources.
Memory usage in macOS can be viewed by using the informative built-in Activity Monitor, stashed inside the Utilities Folder. To launch Activity Monitor, open Finder and select Applications > Utilities > Activity Monitor. You can also use Spotlight and search for Activity Monitor. Once you have Activity Monitor open you’ll be presented with a window displaying five tabs along the top in the main pane. Activity Monitor watches more than just how much physical memory is being used. It also monitors CPU usage, which apps are using the most energy, how apps are reading or writing from your hard disk or SSD, and what’s going on with your network. Click on the Memory tab and you will be brought to a whole breadth of useful information to assist us in memory management and where our discussion will focus.
The Memory tab window lists out all of your running applications and processes along with their individual memory usage. If you look at the bottom of the window it contains a Memory Pressure graph and information tables breaking up what is composing the graph.
The Memory Pressure graph illustration helps make it quick and easy to glance at the availability of macOS memory resources. The graph moves from right to left and updates at the default system set intervals. You can change the frequency from the default setting of Normal 5 sec to either Often 2 sec or Very Often 1 sec by navigating to View > Update Frequency in the Activity Monitor’s menu bar.
The current state of memory resources is indicated by the color of the graph. If it’s green, everything is working as it should be and memory resources are available. Yellow means resources are still available but they’re being tasked by memory-management processes such as compression. Cached files, essentially apps that are no longer active, but still have their data stored in RAM, are being compressed to create enough free memory to assign to the apps requesting an allocation. When memory is compressed, it requires some CPU overhead to perform the compression, but this small performance hit is minor, and probably not noticeable to you. Red indicates compression has reached its limits, your Mac’s memory resources are depleted, and macOS is using your hard drive for memory. When the memory pressure chart begins to reach this level, you really need to free up some memory as soon as possible by quitting one or more applications. This could also be an initial indicator that your Mac may need more physical memory installed if this is a typical level you find your macOS running at over time. To find out which process is at fault, we will now move our attention to the main pane of the memory tab.
In the main pane you will see a list of both open applications and system processes along with their individual stats. You can add additional columns to view in the main pane by going to the View > Columns menu. Expand the Columns option, choose the ones you want to view, and they’ll appear in Activity Monitor. You can also sort the list of processes by any of the columns in ascending or descending order. Click the column title once or twice to change the order. On the top right there is a Search Filter box which lets you search for a specific process if you know exactly what you’re looking for. I always like to sort by descending usage when investigating as I can see right away what the primary culprits are.
Notice how many items appear in the Process list, even when you have no applications open except Activity Monitor running. Some applications are easy to spot, while others are background system level operations you don’t normally see or directly interact with. As soon as you see an application persistently using a large percentage of memory that you are not actively using, you should ask yourself if you really need to have it open and then consider closing it. You should avoid the temptation to close a process if you don’t know exactly what that process is doing. Ignore processes which have “root” listed as the user and focus on those running from your user account. Reason is that many of these are system level processes that are required for computer to function properly. If there are some process really taking up a lot of memory and you don’t know what it is doing, some quick research online should be able to assist you.
Now that you are able to see what is gobbling up all your memory what can you do to help alleviate the problem macOS is experiencing? In my third and final Tech Tails article for this series, I will be sharing some tips on ways to relieve and free up memory to help get that youthful spring back into your Mac.
Until next time…happy computing!