Upgrading the RAM in your Mac can provide a significant boost to performance, as well as equipping the machine to run demanding software in the future.

On older models this is actually a very simple procedure, and if you use third-party RAM from companies such as Crucial you'll find the cost quite affordable too. Modern Macs are a different story, and there are plenty of pitfalls you need to avoid - which is why we've put together this guide.

For more general advice on adding to your system's capabilities, see How to upgrade a Mac.

Should I update my RAM?

Random Access Memory (RAM) is a temporary storage medium used by your Mac's CPU. Essentially, it's a short-lived storage space where data for processes is kept whilst you're running them. Your CPU can access the data stored in RAM far faster than it can information held on a hard drive for example. This makes it vital to the smooth operation of your Mac.

So, is it a good idea to upgrade your RAM? Well, in many instances - yes. Put simply, RAM upgrades are one of the cheapest and easiest ways to get new life out of an old Mac. And for many models, the only tool you'll need is a small screwdriver.

But before you do, you might want to run through these tips about how to free up memory on your Mac.

Risks of updating Mac RAM

However, there are a few reasons why you might end up regretting updating your RAM.

You could damage your Mac: There is the chance that if you don't take proper antistatic precautions (which we will cover later) you could damage the sensitive electronic components inside your Mac. If you work carefully and follow the instructions you should be fine, but you undertake this work at your own risk, and Macworld does not accept responsibility if you short your motherboard or suffer similar problems.

You should check what affect a RAM upgrade may have on your warranty: As a general rule, RAM is deemed as a 'user serviceable' part and, as such, you won't invalidate your warranty by upgrading it.

However, in the case of many modern Macs - particularly Mac laptops - Apple might specify that the memory (RAM) is not removable by users and indicate that if the RAM is to be updated it should be done by an Apple Authorized Service Provider.

With that in mind, it may be worth checking the manual of your Mac for the term "user-serviceable" to confirm this. Of course if your Mac is out of warranty then you have no reason to worry about invalidating anything.

The RAM might not be accessible: In some Mac models the RAM is soldered into place (e.g. 21.5in iMac 2015) so it is impossible to upgrade, and if you tried you would likely damage your Mac.

How much RAM do you need?

Without taking a look at your Mac's Activity Monitor at peak usage, it's impossible for us to say how much RAM you really need.

How to upgrade RAM in a Mac: Memory Used

As a rule of thumb, 16GB is probably the most that anyone who's not into video editing or running multiple virtual machines will need. But this is for today - a better question, perhaps, would be how much will you need years from now?

The basic principle behind Mac future-proofing is making your current hardware powerful enough to deal with the inevitable increase of software demands over the next few years. And it's always better have a little more than you need rather than less.

Our advice would be to always bear this in mind when you are buying a new Mac. There are various build-to-order options when you purchase a new Mac from Apple, and you should get as much RAM as you can afford.

Can I add RAM to my Mac?

We'll go into more detail about how to add RAM to various Mac models below. But in summary, you can add RAM to the following Macs:

  • MacBook: Only the 2008 to 2011 models.
  • MacBook Pro: 2009-2012 13in, 2008-2012 15in, and any 17in model can be updated. If you MacBook Pro has a Retina display the RAM can't be updated.
  • MacBook Air: You can't update the RAM in any MacBook Air models.
  • iMac: The RAM can be updated in the majority of iMacs, with a couple of exceptions: the 21.5in models from Mid-2014 and Late 2015 had their RAM soldered into place.  
  • Mac mini: 2010 - 2012 models can be updated, as can the 2018 Mac mini. 
  • Mac Pro: You can add RAM to any model.
  • iMac Pro: RAM isn't user-accessible. If the memory in your iMac Pro needs to be replaced, Apple suggests you contact an Apple Store or Apple Authorized Service Provider.

What RAM is compatible with your Mac?

Before you upgrade, you need to find out what kind of RAM is actually compatible with your Mac.

Non-upgradeable soldered RAM

Before we start, it's worth mentioning that not all Macs allow for RAM to be upgraded. On some models, particularly MacBooks, the RAM is soldered on - making removal near impossible and hazardous to your computer. In these models you really want to buy as much as possible at the point of purchase to 'future proof' yourself.

Theoretically it's possible to upgrade soldered RAM, but it is an extremely difficult process that can very likely result in the irreversible destruction of your Mac - and we certainly wouldn't recommend it. You can see REWA Technology upgrade the RAM in a 2015 MacBook Air in this video.

Types of RAM

Now, assuming your Mac's RAM is upgradable, there are a number of technical figures used in the description of RAM, two main pieces of information you need are the 'double data rate' variety (i.e. DDR3), and the frequency (i.e.1600 MHz). It can also help to know your Mac's Model Identifier (i.e. 'MacPro6,1')

If in doubt, ask: If you're even a little unsure before purchasing, ask your potential RAM vendor to confirm that the components in question are compatible with your Mac. That way you're covered.

The first and probably simplest method is to use 'About This Mac'.

  1. Click the Apple logo at the top left corner, and choose 'About This Mac'
  2. Look at the figure given for memory in the 'Overview' tab (e.g. 1866 MHz DDR3). This will tell you the kind of RAM you need
  3. Then click on System Rport.
  4. Now click on 'Memory' in the lefthand column. It will tell you how many memory slots you have available, and how they are being used. Can I update RAM in MacBook Pro
  5. You'll also be able to see if the memory is upgradable - in the case of the MacBook Pro above it's not.

An alternative method of identifying the correct type of RAM is to use Crucial's free scanner.

Where to buy RAM

There are a variety of ways to purchase RAM. As a general rule, cheaper = riskier.

Method 1: Direct from Apple (most expensive)

You can buy your RAM directly from Apple. It is usually the most expensive option by far and, considering that there are compatible aftermarket versions that work just as well, and are cheaper - it is not our recommended option.

Apple hasn't currently got a RAM section in its store, so your best bet may be to go to Apple UK or Apple US and run a search for 16GB RAM or 32GB RAM, depending on how much you want to buy.

At time of writing the company sells the following RAM modules:

If you read the description of each product, you'll notice that the company doesn't always tell you which Macs the RAM in question is compatible with (usually it does this only if it's for a current Mac). So be very careful about ensuring it's the right kind of RAM before buying.

As we said above, you are best off buying your RAM at the point that you buy your Mac, as it will be built-to-order with the RAM you require installed.

Method 2: Reputable aftermarket supplier (less expensive)

This is our recommended approach: buying your RAM through a reputable aftermarket supplier. There are plenty of places to buy RAM online, but, as with most things, established and reputable companies with warranties and return policies are your best bet.

In the world of aftermarket Apple hardware, a few names have stood the test of time. MacUpgrades, Crucial and OWC (via Megamac) are three of our favourites.

Method 3: Certified refurbished (cheaper still, but shorter warranty)

RAM refurbished by Apple or another (presumably Apple approved) company is often referred to as 'certified'. Refurbished RAM is much less common than, say, refurbished Macs, but it does exist. Certified refurbished is often backed with a warranty, though this is often shorter than Apple's warranty.

Method 4: Secondhand (least expensive by far, but riskiest)

We don't recommend this. Done right, this is usually the cheapest method. It's also the one most fraught with risk, as there is often no warranty - and no returns. You could save hundreds, or you could end up wasting money on something that doesn't work. Caveat emptor.

There are plenty of places to buy secondhand - but when it comes to choice, eBay is probably the undisputed champion. You could also try AliExpress (which also has a lot of choice), eBid or Gumtree.

What to do before replacing your RAM

Although RAM upgrades are simple (as far as upgrades go) there are still some basic precautions that you should take when handling sensitive electronics and accessing the inside of your Mac.

The aim here is to prevent any damage caused by static electricity. This can occur when you touch an object which conducts electricity at a different electrical charge to you (yes, you conduct electricity too).

First, shut down your Mac and wait at least 10 minutes for the internal components to cool.

Make sure that you keep your RAM in its antistatic packaging right up until you need it. When you're ready to start, touch an unpainted metal surface in your computer to discharge any static in your body. Try to ensure that your workplace is as static free as possible, remove any plastic bags or other objects that can cause static build up.

Keep your Mac plugged in, but turned off. This can help ensure that the case is grounded - which reduces the chance of any discharge. The particularly hardcore may consider using an antistatic wrist or heel strap to really minimise charge build up - but this isn't essential.

When mounting your RAM, ensure that the small notch cut into the front facing gold contacts matches up with the protrusion in the receiving bay. Mounted correctly, it will slot in, jigsaw-like - if mounted the wrong way, the protrusion will prevent the RAM from fully connecting.

How to upgrade RAM in a Mac: Technical precautions

How to upgrade MacBook Pro RAM

After the arrival of the Retina display, upgrading your Mac laptop, be it MacBook, MacBook Air or MacBook Pro became nearly impossible.

Models produced prior to this are relatively straightforward, though there are some obvious structural differences in the design of the Air, Pro and original MacBook. Here's an example of a MacBook Pro 17in Unibody.

MacBook Pro 17in Unibody

What you need: Phillips head screwdriver.

Notes: As previously mentioned, RAM upgrades are currently not an option in any Retina MacBook Pro models.

Apple provides an illustrated guide for memory upgrades. Just click Apple > About this Mac, and click the Memory tab then the Memory Upgrade Instructions link.

  1. Remove the screws that secure the lower case to the upper case and then detach the lower case. You will now see the inside of your Mac.

    How to upgrade RAM in a Mac: MacBook Pro

  2. Remove the black battery by gently pulling the plastic tab towards the front of the device. If it doesn't have a tab, you should be able to carefully lever it out yourself, a spudger may help with this. How to upgrade RAM in a Mac: MacBook Pro
  3. Release the tabs on either side of the RAM by simultaneously pulling each tab away from the chip. The tabs hold the chip in place, and once released, the RAM should loosen.
  4. Gently remove the now loose RAM from the socket, repeat the process if you wish to remove any further chips.
  5. To install new RAM, just follow the preceding steps in reverse.

Looking for instructions for a different model? Take a look at our Mac upgrade guide.

How to upgrade Mac mini RAM

Up until late 2014 the Mac mini was a very easy device to upgrade yourself. Simply unscrew the plastic base and there were two pop-up RAM slots into which you could place new chips. If you have one of these models then it's probably fitted with 4GB of RAM, as that was the standard Apple issue.

Sadly the 2014 Mac mini removed the manual upgrade feature of its predecessore. It was only possible to upgrade at point of sale, otherwise it came with 4GB fitted, which can be increased to either 8GB for £90/$100 or 16GB for £270/$300. The two higher models both come with 8GB of RAM, which again can be increased to 16GB.

For years the Mac mini was not particularly 'RAM upgrade friendly' with quite a lot of variation in the internal layout of the various models, which meant that some require more disassembly than others. There is sometimes the need to unplug components on the logic board, which can end badly if you're not careful.

When Apple updated the Mac mini in 2018 changes were made that made it more upgradable thankfully. That machine can accomodate up to 64GB RAM.

Today on memory chip retailer Crucial's website you can buy an 8GB kit for £59.99 or 16GB kit for £91.19, (both for the 2012 genertion Mac mini) or a 16GB kit for £92.39 and a 32GB kit for £179.99 (for the 2018 Mac mini).

Depending on the model you're working with, it's likely that you'll need some kind of flat implement to get the top cover off (blunt, not sharp). Don't let that stop you, though - our colleagues in the US managed to do it in a mere 6 minutes, but it was a very old Mac mini model.

Mac mini A1176 "Core Duo"

What you need: Putty knife or equivalent blunt implement, screwdriver with a thin shaft, spudger/nylon probe tool, tweezers.

  1. Flip your iMac over and insert your knife into the crack between the top and bottom housing. Your aim here is to use the implement to separate the internal plastic clips on the bottom of the housing, and which are clasped to the top case.
  2. Gently use the knife to separate the top and bottom cases, this should release the latches and start to lift the lower housing on the side on which you are pushing the implement.

    How to upgrade RAM in a Mac mini

  3. Once you've loosened this side, move to another side of the Mac and do the same thing. There are clips on every side holding the cases together.
  4. Our aim is to release all of them with the implement, whilst gently pulling upwards on the lower casing to help release it. You may want to work all the way around the perimeter in a circle.
  5. The latches, now loosened, should allow you to separate the top and bottom housing, so turn your Mac Mini back over and separate the two parts.
  6. To get to the RAM, you're going to need to remove the internal frame which sits above it.

    How to upgrade RAM in a Mac mini

  7. Start by removing the Airport antenna (this is the larger of the two, and is located near the power button). You do this by very gently squeezing the two arms together, whilst lifting the antenna. They are delicate, so be cautious - and you'll need to put them back in when you seal the Mac up again.
  8. Use your spudger to gently lift the ZIF cable lock from the socket. It will lift about 1mm - don't try to fully remove the cable lock, you could damage it.How to upgrade RAM in a Mac mini
  9. Now lift the audio board ribbon cable out of its socket. If it doesn't move, that means you've not fully released the ZIF cable lock. Go back a step and check to see that you've lifted it properly - gently does it.
  10. Now use your tweezers to lift the hard drive's thermal sensor cable out from the logic board. It's located under the optical drive opening. You want to grab the connector, not the wires.

    How to upgrade RAM in a Mac mini

  11. That's the hard bit done. Now that you've removed all the cables that hold things together, all you have to do is unscrew the four Phillips screws securing the internal frame to the bottom case.
  12. Find the four screws and unscrew them. The longest is located near the Mac's sleep light.
  13. Once you've done that, gently remove the internal frame from the bottom case - be careful not to catch any delicate cables as you lift the internal frame.
  14. With the internal frame removed, the RAM should now be accessible.
  15. Pull the ejectors on each side of the chip simultaneously, which should cause the RAM to release. Then pull the now loosened RAM out from the bay. Repeat this process for the same to the RAM in the next bay, if required.
  16. To add the new RAM, ensure that the RAM is facing gold contacts down then, holding both ends of the RAM, gently push downwards into the bay until the ejectors secure the RAM.

Trying to upgrade the RAM on a different model to this? We may have you covered in our Mac upgrade guide.

How to upgrade iMac RAM

Upgrading an iMac's RAM is, at least in the case of the 27in model, easier than upgrading its other components - as it doesn't generally involve removing the screen.

It is a lot easier to upgrade the RAM in a 27in iMac than in the 21.5in iMac because the 27in model has a convenient memory access door, located centre beneath the screen - where RAM can be accessed. In that case updating the RAM is simple, you just need to make sure you purchase the correct RAM and you are all set.

However, the RAM in the 21.5in iMac can be a little more tricky to update, and in some generations (namely the Mid-2014 and  Late 2015 models) it's impossible to update due to being soldered into place.

Thankfully, Apple's stopped soldering RAM in place in recent years. Now even 21.5in iMacs can be upgraded, but it's a challenge best left to an Apple Authorized Service Provider.

If you have an older iMac you can update the RAM in it yourself. Here's an example:

iMac (21.5in, Mid 2010)

What you need: Phillips head screwdriver.

Notes: Apple provides an illustrated guide for memory upgrades: just click Apple > About this Mac, and then click the Memory tab and then the Memory Upgrade Instructions link.

  1. Lay your iMac face down on a clean, soft surface. We recommend that you place a towel beneath your Mac and your work surface - you don't want to scratch your screen.
  2. Find the RAM access door at the bottom of your Mac. Loosen the three screws that secure it, they should remain inside the access door, then remove the door.

    How to upgrade RAM on a Mac: iMac

  3. Carefully slide the black RAM pull tab out of the slot.
  4. Firmly push this tab to eject the module on this side of the RAM bay.
  5. Slide the RAM module out of its slot in the bay, and set aside. Repeat this process to remove RAM modules from other bays.
  6. Ensure that replacement RAM modules are correctly oriented, and then gently slide them into the iMac. Make sure they're mounted by using your thumb.

27in iMac (Late 2012 model)

  1. Place it flatscreen down on something soft (such as a towel or blanket) to protect the screen.
  2. Press the small button at the top of the power socket, and pick out the memory hatch door above it. This is quite possible to do using just your fingers.
  3. Try to avoid using something to help lever the door open as you might scratch your Mac. Get someone with longer, strong fingernails if that helps. You really don't need much pressure to open this door.

    How to upgrade RAM in a Mac: Open iMac memory hatch door

  4. You'll now see the two 4GB memory DIMMs that Apple ships as standard with its iMacs. The company illustrates how the RAM should be fitted on the back of the memory hatch door.

    How to upgrade RAM in a Mac: 27in iMac memory install DIMM instructions

  5. Now pull out the little arms to raise the iMac RAM slots.
  6. Add your two new DIMMs in the empty slots. There's no need to remove the existing memory chips, unless you're adding four new 8GB DIMMs for the maximum 32GB memory installation.

    How to upgrade RAM in a Mac: 27in iMac memory install DIMM slots 3

  7. Press back the small levers so that the DIMMs are back flat.

    How to upgrade RAM in a Mac: 27in iMac memory install DIMM slots 4

  8. Put the door back on so that it clicks back into place. You don't need long fingernails for this!

Looking for instructions for a different model? Take a look at our Mac upgrade guide.

How to upgrade iMac Pro RAM

It might look like the same exterior design in most respects, but the iMac Pro hasn't got the same user-accessible hatch as the iMac, so you can't upgrade its RAM yourself.

How to upgrade RAM in a Mac: iMac Pro

The good news is that you can get the RAM upgraded, you just need to go to a service centre and ask them to upgrade it for you. Rene Ritchie says this doesn't need to be an Apple Store - it can be an independent outlet.

How to upgrade Mac Pro RAM

The Mac Pro used to be is Apple's most 'upgrade-friendly' product. Even the 2013 Mac Pro had a memory bay, although it is somewhat fiddly to access.

The RAM inside Apple's new Mac Pro when it launches later in 2019 should be easily upgradable.

Mac Pro Cylinder (2013)

What you need: Nothing.

Notes: It's worth bearing in mind that the memory latches are not very sturdy and prone to bending if you're not careful. OWC provides a 'nylon pry tool' (AKA "Spudger") for just this, but it's not entirely necessary - a little gentleness and a little patience go a long way.

Apple provides an illustrated guide for memory upgrades: just click Apple > About this Mac, and then click the Memory tab and then the Memory Upgrade Instructions link.

  1. Slide the lock switch right, to the unlocked position, then slide the outer case upwards and off the Mac Pro.
  2. Push the RAM release tab upwards (in the direction of the white arrow). This will cause the RAM slots to release outwards, and allow you access to the modules.

    How to upgrade RAM in a Mac Pro

  3. Gently, but firmly, grasp the top and bottom of the RAM module and pull it out of the slot.
  4. To install the new module(s) ensure that it is oriented correctly, and then push the ram into the slot, make sure that you apply pressure to the top and the bottom of the chip, to ensure that it is fully mounted.

    How to upgrade RAM in a Mac Pro

  5. Push the tray back into the body of the Mac Pro and then replace and lock the case.

Mac Pro Tower (2006-2008, 2009-2012)

What you need: Nothing.

  1. Lift the locking lever on the back of the case to unlock the side panel, then remove the side panel.
  2. Locate the RAM tray at the bottom corner of the Mac Pro.

    How to upgrade RAM in a Mac Pro

  3. Simultaneously push downward on the ejectors on each side of the RAM stick; this should cause the RAM to release. Then carefully lift the stick out.

    How to upgrade RAM in a Mac Pro

  4. Ensure that the new stick is properly oriented, then carefully push the stick down into the bay with both hands, ensuring that you put some pressure on both ends of the stick. You should hear a click as the ejectors lock the stick in. Make sure both ejectors are secured.

What to do after replacing your RAM

Once you've completed your upgrade, it's a safe bet to run a memory test on your new modules - to ensure that everything actually works.

Why? Often it's not obvious if a piece of RAM is not up to par. Occasionally a defective chip will make its way through the manufacturer's quality tests - and a memory test can help you prevent problems before you start to experience crashes and similar calamities.

Recommended: Memtest

One of the most popular pieces of software for this is Memtest, which is available free from here.

It's easy to use. First, download the project folder as a zip.

How to upgrade RAM in a Mac: Memtest

Then unzip it, and run the Memtest unix executable.

How to upgrade RAM in a Mac: Memtest

The software will run on a test sequence in a terminal window. Close as many applications as possible before running the test - this gives Memtest as much RAM as possible to work with.

How to upgrade RAM in a Mac: Memtest

Voila.

Some alternatives

If for some reason Memtest is not for you, there are a number of alternatives in the App Store - search for 'Memory Test' software, but check the reviews first. We've not tested any of them and can only vouch for Memtest.

You can also use your Mac's inbuilt memory tests. Restart or boot up your Mac, and hold D whilst it boots - this should take you to the diagnostics screen. What actually comes up at this point will depend upon your OS, but somewhere in the options should be a section called 'Hardware Tests' - in which you'll find the option to test your memory.