First time checking out this series? You’ll get the most value by starting at the beginning, however you can also use the series overview if you’d like to go buffet style.

Note for regular readers, the already tech savvy, and IT professionals: this series is designed as a resource you can share with those you are helping or for those looking to become tech savvy on their own.

How to size up a slow Mac and what to do next

Background, Expectations, & Best Practices

One of the best things about a Mac is that they often last a long time. While this is a great feature of a quality product, your Mac’s performance may also decrease the longer you own it. And even if you have a new or relatively new Mac you’ll likely find some value in the tips below.


We’re going to take a look at Activity Monitor which is built-in to macOS and provides a great way to check your Mac’s system resources and how it’s doing. It can also give us some direction in improving performance.

To open Activity Monitor use Spotlight (click on the magnifying glass in the menu bar in the top right corner) and type in Activity Monitor. Alternately, you can click on Finder (the blue and white smiley face icon in your dock, usually left hand side) and then click on Applications → Utilities → Activity Monitor.

You’ll now see a window like the image below.

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At the top you’ll see five tabs, click on Memory. At the bottom of the window we’ll see details for how much memory your Mac has, how it’s allocated and how much pressure your memory is under.

In the middle of the window you’ll notice individual applications and system processes that are using resources, but we won’t get into manipulating those for now, as it’s a bit more advanced.

If you hover over the different areas in the bottom section you’ll see a description pop up.

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Green in the Memory Pressure section means there are good memory resources available. If you see yellow that means your Mac is utilizing memory management processes like compression and swap to help with the load. If you see red that means that your memory resources are depleted.

If you keep an eye on your Mac and regularly notice memory pressure in the yellow or red you can quit applications to reduce the load, shut down your Mac, or potentially install more RAM (random access memory, which is different from your hard drive or solid state drive).

You can find compatible RAM for your Mac at Crucial for really fair prices and iFixit has great guides on how to install it for various Macs (not all Macs have user accessible RAM). If you’d like to have an Apple Authorized Service Provider do it, you can locate the nearest one with Apple’s website (Apple stores won’t install RAM upgrades after purchase).

If you don’t shut your Mac down completely very often, starting to at least every 3 or 4 days or even once a week will usually improve performance. When you completely shut down your Mac ( → Shut Down…) this helps clear out cached and compressed files from your memory and will reduce the overall amount of memory used more than just quitting applications.

Above my Mac was using 11.20 GB of memory, and after I quit all applications this dropped to 5.36 GB.

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And here is after shutting down my Mac, you’ll notice memory usage dropped to 3.15 GB, compressed memory dropped to 0, and cached memory also dropped by over 2 GB.

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Another common thing that will slow down your Mac is your hard drive, particularly if it is a hard disk drive (HDD). Depending on your Mac you will have a HDD (hard disk drive) or an SSD (solid state drive) or in some cases a combination.

SSD’s are much faster, quieter, and more reliable on the whole as they don’t move to operate. In contrast, HDD spin at either 5,400 or 7,200 rpm to operate and have high storage capacities for affordable prices, but are much slower, less reliable, and produce more heat.

Most iMacs typically come with a HDD with a high capacity (although some include a Fusion Drive which is a combination of both HDD and SSD). Almost all of Apple’s new notebooks come with the faster SSD’s, but some older models particularly the 13-inch MacBook Pro (without Retina display) came with a HDD.

You can find out which you have by clicking  in the top left of the menu bar and then About This Mac → System Report → SATA/SATA Express. If nothing shows up there, click on Storage just below SATA/SATA Express. Look for references to solid state/SSD or hard disk drive/HDD.

If you have a SSD, your drive is not likely causing your slow performance. However, if you have a HDD and you see the color wheel or beachball often and experience slow performance, upgrading to a SSD could really improve your Mac’s performance.

I ended up doing this with my 2011 iMac and it has really improved performance to the point where I’ll probably use it for a few more years. Usually SSD’s are about 5-10 times faster than a hard disk drive (HDD) depending on what you buy.

A hard drive upgrade is quite a bit more complicated than upgrading your memory (RAM) so this will likely be best left to an Authorized Repair Provider. Although if you’re already out of warranty, feel comfortable doing so, or just feel like getting a bit dangerous, iFixit has superb walkthroughs and you can pick up a fantastic SSD from Crucial starting under $100.

A good middle ground that will still save you money may be checking with your local repair provider to see if you could bring in your own drive for them to install.

Do This

1. Keep an eye on your memory usage with Activity Monitor to see if your Mac is running slow due to low memory. Look into RAM upgrade options as shared above.

2. If you have a hard disk drive (HDD) weigh the option and costs of upgrading to a SSD.

3. Also take a look at how much storage you have used and how much is available. This is relatively quick and easy to do and may help improve performance. It’s often recommended to leave 10-20% of your drive space free. Check out our article on how to efficiently free up space and recover lost storage on your Mac.

4. These are many other factors that could be causing your Mac to run slow, but these are two major aspects to look into. As always feel free to ask any questions in the comments below.

Next Week: How to approach updating software on iPhone and iPad

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