How (And Why) To Install More RAM In Your iMac

When it comes to breathing new life into a computer that’s beginning to show its age, two go-to upgrades are guaranteed to add more snap to the user experience: dumping the hard drive for solid state storage (SSD) and adding more RAM.

Unfortunately, with Apple ’s all-in-one iMac, installing an SSD is complicated and probably not the best choice for a DIY project; however RAM upgrades are easy. At least for most Macs. Apple’s 21.5-inch iMacs have moved to non-user replaceable memory since mid-2012, but with prior versions and all 27-inch and 24-inch models, installing RAM is a five minute operation.

Why install more RAM? Easy. You can never have too much of it. The more RAM your iMac has at its disposal, the more windows or tabs you can have open without the system bogging down. With more RAM, the operating system isn’t making calls to virtual memory (which uses the hard drive and slows things down considerably).

Apple publishes guidelines for the maximum amount of RAM each iMac model supports, however the company is known for being conservative and memory upgrade specialists have discovered many iMacs are actually capable of supporting twice the amount of RAM Apple suggests. That could be great news if your iMac is currently equipped with the maximum amount of RAM and you’re hitting a performance ceiling. The model I most recently upgraded is a 2011 vintage 27-inch iMac and although Apple lists it as supporting a maximum of 16GB of RAM, in fact it will recognize and utilize 32GB. To find out how much RAM your iMac will really support, a site like EveryMac that tracks this data is worth checking out.

Note that you still need to follow Apple’s requirements for technical specifics of the RAM. In the case of that 2011 iMac, it requires PC3-10600 unbuffered, nonparity 1333 MHz 204-pin DDR3 SDRAM. Buy in matching pairs for maximum impact. The easiest way to make sure you have the right stuff is to shop at a retailer that sells RAM specifically certified for Mac use. You can usually enter your model number and it will spit out the options without any fuss or nail-biting over compatibility.

Once you have the RAM in hand, it’s time to install. And it really is as easy as I suggested. Here’s how you do it.

1. Back Up Your Data

This is the worst part of the operation. Unless you’re smart and keep an incremental backup going at all times, then you’re golden. Otherwise, do a backup. It’s unlikely you’ll have a problem, but any time you’re making a significant change to a computer --hardware or operating system-- back up.

2. Prepare the iMac

Put a towel on a table, unplug your iMac and lay it display-down on the towel. Give it a few minutes to cool down (it gets surprisingly hot). When it’s in this position, I like to grab a can of compressed air and blow out all the heating and air vents located on the bottom and back of the computer. Keep cats and dogs away, keep the RAM DIMMs in their antistatic wrapper until the last possible moment and touch a grounded object to discharge any static charge you might have.

3. Open the Memory Compartment Door

Newer 27-inch iMacs have a nifty pushbutton hatch on the back directly beneath the stand mount. Push the button and pop off the door. Everyone else (and as pictured below), you’ll find the memory compartment door on the bottom edge of the iMac, secured by three Phillips screws. Remove the screws (don’t worry, they’re secured to the door so they won’t fall out) and take off the door.

4. Remove any RAM you are Replacing

If all the RAM slots are filled, you’ll be removing existing DIMMs and replacing them with the new higher capacity versions you bought. If your iMac has the back-mounted memory compartment, you’ll find a pair of levers holding the DIMMs in. Pull those levers toward you, releasing the DIMMs, and remove the ones to be replaced. Older iMacs will have two plastic pull tabs (as pictured below). Pull the tab gently and it unseats the DIMMs, which you then pull straight out.

5. Install the New RAM

Slide the new DIMMs into the empty slots and gently push them until there’s a slight click and they seem firmly seated. Don’t force the DIMM. If it won’t seat properly, you may have it upside down. When the RAM is installed, push the levers back down (new 27-inch iMacs), tuck the pull tab into the compartment (everyone else) and replace the memory compartment door.

That’s it. You don’t have to do any key combos or special start-ups to get your iMac to recognize the RAM, simply power it up. When you check About This Mac you will see the new RAM amount installed. If you want, within the displayed window, click the Memory tab and it will display how much RAM is installed in each slot. If you want even more details, go back to Overview, select System Report, navigate to Memory and you can see all the technical details of each DIMM installed, including its status.