How to Change RAM on an iMac

The iMac is a very capable system that combines a quality display with a powerful set of hardware. The iMac is used by a wide range of users for everything from everyday home applications to video editing. One of the most common upgrades made to the iMac is a RAM upgrade. This can be performed by the user without sacrificing warranty or the need of any tools other than a Phillips-head (also known as crosshead) screwdriver.

The first thing you’re going to want to do is make sure that you’re getting the right aftermarket RAM for your iMac. Apple provides a detailed outline of the RAM you need, depending on your model of iMac here. All you need to know is the year and size of your iMac.

On Lion, this can be done by going to About This Mac and clicking More Info. You can also determine the model using the model number and this guide: How to Identify iMac Models.

Once you’ve determined what kind of RAM needs to be purchased, it’s a good idea to buy RAM in matching pairs. Upgrading by adding a single stick is okay, but there are some benefits to be had by pairing RAM. If you’re upgrading RAM on an i3, i5, or i7-based iMac, it’s important to note that it will not start with a single DIMM installed on a bottom slot. You can get it to start with a single DIMM placed in a top (closest to the display) slot, however. iMac models running on Core 2 Duo processors can operate using a single DIMM in any of the four slots.

To access these slots, you’ll need to unplug your iMac and lay it face-down on a flat surface, preferably covered by a soft cloth that won’t scratch the glass. At this point, you’ll want to raise the stand so you have clear access to the memory panel along the bottom of the iMac.

By unscrewing the three screws, you’ll expose all four RAM slots. You can eject the existing ram by pulling on one of two black strips, which should be tucked around the center of each column of slots. If the DIMM doesn’t release from a slight tug, don’t worry. It can take a firm, sustained pull to knock them out of place.

Now you’re ready to install the new RAM. The DIMMs should be installed in the top (towards the display) side first. If you’re installing two DIMMS, you can add the previously-installed RAM to the bottom slots to increase the overall memory even more. It’s a good idea to pair equal amounts of RAM side-by-side. For example, my iMac has two 4 GB DIMMs in the top slots and a pair of 2 GB DIMMs in the bottom. You’ll know the DIMM is installed correctly when you hear a clicking sound and the RAM is stable and even within the slot.

Once the RAM is installed, replace the black ribbon so that it covers the center of any sticks and tucks in the other side. The bottom panel should be replaced and the screws secured. The panel easily comes out of alignment during replacement, so the best way to do this is by loosely fitting each screw in place before tightening them all down.

After this is done, replace your iMac and start it up. If you receive any errors during startup, you may need to reseat the memory and make sure that the DIMMs you’re using are compatible with your Mac. You can check to see if the Mac recognizes the new RAM by clicking the little Apple in the upper-left corner of the screen and selecting About This Mac. If the amount of RAM listed matches what you should expect after the upgrade, you’re good to go.

Article Written by

Ryan Matthew Pierson has worked as a broadcaster, writer, and producer for media outlets ranging from local radio stations to internationally syndicated programs. His experience includes every aspect of media production. He has over a decade of experience in terrestrial radio, Internet multimedia, and commercial video production.

  • Anonymous

    I find it hilarious that I found this on Google+ about 2 hours after I installed my upgrade. :)

    • http://facebook.com/yajtyler Jay Tyler

      same here!!

  • D Babbra

    I’ve just done 4Gb to 8Gb (2x4Gb) on my Core 2 Duo which only had 2 memory slots. Also upgraded to Snow Leopard – can’t say the overall change is blistering ! I’ll wait for a service pack before moving to Lion. My future concern is will Core 2 Duo still be supported at 10.7 (Hot Lion?).

    • http://www.facebook.com/profile.php?id=100000369278419 Chris Licata

      Well there are no more service packs for Snow Leopard in fact there never were. Thats only a windows thing. And second Lion runs great on Core 2 Duos just make sure in about my mac that it is a core 2 before you buy lion

      • Diljit Babbra

        Thanks Chris. I am definitely C2D. I will move to Lion before long but I do wonder if C2D will be a casualty post-Lion. Would you know if Lion at £20 is a multii-mac pack?

  • Anonymous

    I just p a i d $21.87 for an i P a d 2-64GB and my boyfriend loves his Panasonîc Lumîx GF 1 Camera that we got for $38.76 there arriving tomorrow by UPS.I will never pay such expensive retail prices in stores again. Especially when I also sold a 40 inch LED TV to my boss for $657 which only cost me $62.81 to buy.
    Here is the website we use to get it all from,
    http://bit.ly/Bid1st

  • http://twitter.com/RobinKanters Robin Kanters

    I personally think Microsoft is generating a lot of false expectations. For as far as I have seen, the ‘new’ features Windows 8 is going to have feel more like an application than an Operating System…

  • Anonymous

    I just p a i d $21.87 for an i P a d 2-64GB and my boyfriend loves his Panasonîc Lumîx GF 1 Camera that we got for $38.76 there arriving tomorrow by UPS.I will never pay such expensive retail prices in stores again. Especially when I also sold a 40 inch LED TV to my boss for $657 which only cost me $62.81 to buy.
    Here is the website we use to get it all from,http://bit.ly/Bid1st

  • D Lowrey

    Head back and find out all the promises MS has made throughout the years for every product they have had a hand in. Time and again…promised features turn out to be vaporware. With their history to back them up…we will see MS do the same exact thing again and again.