Experience workstation-class performance in the iMac form factor with the space gray Apple 27' iMac Pro with Retina 5K Display. Featuring a 3.2 GHz Intel Xeon W 8-core processor and 32GB of 2666 MHz DDR4 ECC RAM, the iMac Pro is designed to handle demanding pro workflows such as pro photo work, pro video editing, advanced graphics editing.
Best answer: You can! The information is a bit buried in the spec sheet, but Apple's official website confirms it.
- Fastest processor yet: 27-inch iMac (From $1799)
- RAM upgrade: Crucial 32GB DDR4 Memory kit ($207)
The 27-inch iMac still has a backdoor for RAM
One of the biggest deciding factors for some people have in figuring out whether to buy the 21-inch iMac or the 27-inch iMac is aftermarket upgradable RAM. The 21.5-inch does not allow for post-purchase upgrades without invalidating your warranty.
The 27-inch iMac is the only iMac that allows for aftermarket upgrades to RAM. That means, you can buy additional RAM (up to 32GB) any time you want, long after you've bought your new iMac.
The 27-inch iMac does have user-accessible RAM upgrade slots. From Apple's website:
Memory: 8GB (two 4GB) of 2666MHz DDR4 memory; four SO-DIMM slots, user accessible [emphasis added].
You're good to start with the lowest RAM and upgrade later when you've recovered from that hefty purchase.
I've done this with two 27-inch iMac computers. Each time, I postpone a RAM upgrade until I need it, which gives me time to save up a little extra cash and keeps me from spending money unnecessarily.
The 21.5-inch iMac is still off-limits
Back in 2012, Apple shut off aftermarket RAM upgrades for the 21.5-inch iMac. RAM was relocated under the logic board, so it was no longer accessible without having to take apart the entire iMac.
These days, if you want to attempt a DIY RAM upgrade on the 21.5-inch iMac, you'd need a lot of experience and a special upgrade kit, something like the ones iFixit sells. Of course, doing so will void your warranty, so it may not necessarily be worth the risk.
If you decide to go with the 21.5-inch iMac, I highly suggest configuring it with the most RAM you can afford at the time you purchase it.
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27-inch iMac (2019)
Apple's 2019 iMac is the fastest it's ever been.
If you're ready to upgrade your iMac, now is the time. With a brand new, faster Coffee Lake processor and AMD graphics, your new iMac is running at top speed.
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Learn how to identify your iMac, then find it below.
| iMac Model | Max. DRAM | User- Installable Slot | AASP- Installable Slot | Video/ VRAM | Notes |
|---|---|---|---|---|---|
| iMac (Retina 5K, 27-inch, 2019) | 64GB | 2666MHz DDR4 | 4GB or 8GB GDDR5 SDRAM | 5 | |
| iMac (Retina 4K, 21.5-inch, 2019) | 32GB | None | 2666MHz DDR4 (for i5 processor) 2400MHz DDR4 (for i3 processor) | 2GB, 4GB, or 8GB GDDR5 SDRAM | 3 |
| iMac (Retina 5K, 27-inch, 2017) | 64GB | 2400MHz DDR4 | 4GB or 8GB GDDR5 SDRAM | 5 | |
| iMac (Retina 4K, 21.5-inch, 2017) | 32GB | None | 2400MHz DDR4 | 2GB or 4GB GDDR5 SDRAM | 3 |
| iMac (21.5-inch, 2017) | 16GB | None | 2133MHz DDR4 | Intel Iris Plus Graphics 640 | 3 |
iMac (Retina 5K, 27-inch, Late 2015) | 32GB | 1867MHz DDR3 | 2GB or 4GB GDDR5 SDRAM | 4 | |
| iMac (Retina 4K, 21.5-inch, Late 2015) | 16GB | None | Intel Iris Pro Graphics 6200 | 6 | |
| iMac (21.5-inch, Late 2015) | 16GB | None | Intel Iris Pro Graphics 6000 | 6 | |
| iMac (Retina 5k, 27-inch, Mid 2015) | 32GB | 1600MHz DDR3 | 2GB GDDR5 SDRAM | 4 | |
iMac (Retina 5K, 27-inch, Late 2014) | 32GB | 1600MHz DDR3 | 2GB or 4GB GDDR5 SDRAM | 4 | |
| iMac (21.5-inch, Mid 2014) | 16GB | None | Intel HD Graphics 5000 | ||
| iMac (27-inch, Late 2013) | 32GB | PC3-12800 (1600) DDR3 204-pin SO-DIMM | 1GB GDDR5 SDRAM, | ||
| iMac (21.5-inch, Late 2013) | 16GB | None | PC3-12800 (1600) DDR3 204-pin SO-DIMM | Intel HD Graphics 4000 | |
| iMac (27-inch, Late 2012) | 32GB | PC3-12800 (1600) DDR3 204-pin SO-DIMM | 512MB GDDR5 SDRAM, | ||
| iMac (21.5-inch, Late 2012) | 16GB | None | PC3-12800 (1600) DDR3 204-pin SO-DIMM | 512MB GDDR5 SDRAM | |
| iMac (27-inch, Mid 2011) | 16GB | PC3-10600 (1333) DDR3 204-pin SO-DIMM | 512MB GDDR5 SDRAM and | ||
| iMac (21.5-inch, Mid 2011) | 16GB | PC3-10600 (1333) DDR3 204-pin SO-DIMM | 512MB GDDR5 SDRAM | ||
| iMac (27-inch, Mid 2010) | 16GB | PC3-10600 (1333) DDR3 204-pin SO-DIMM | 512MB GDDR3 SDRAM and | ||
| iMac (21.5-inch, Mid 2010) | 16GB | PC3-10600 (1333) DDR3 204-pin SO-DIMM | 256 MB up to 512MB GDDR3 SDRAM | ||
| iMac (Late 2009) | 16GB | PC3-8500 (1066) DDR3 204-pin SO-DIMM | 256 up to 512MB GDDR3 SDRAM | ||
| iMac (Mid 2009) | 4GB | PC3-8500 (1066) DDR3 204-pin SO-DIMM | 256 up to 512MB GDDR3 SDRAM | ||
| iMac (Early 2009) | 8GB | PC3-8500 (1066) DDR3 204-pin SO-DIMM | 256 up to 512MB GDDR3 SDRAM | ||
| iMac (Early 2008) | 4GB | PC2-6400 (800) DDR2 200-pin SO-DIMM | 128 or 256MB GDDR3 SDRAM | ||
| iMac (Mid 2007) | 4GB | PC2-5300 (667) DDR2 200-pin SO-DIMM | 128 or 256MB GDDR3 SDRAM | ||
| iMac (Late 2006) | 4GB | PC2-5300 (667) DDR2 200-pin SO-DIMM | 128MB GDDR3 SDRAM | 1 | |
| iMac (Mid 2006) and iMac (17-inch Late 2006 CD) | 2GB | PC2-5300 (667) DDR2 200-pin SO-DIMM | 64MB GDDR3 SDRAM | ||
| iMac (Early 2006) | 2GB | PC2-5300 (667) DDR2 200-pin SO-DIMM | 128MB GDDR3 SDRAM | ||
- Although iMac (Late 2006) accepts up to a 2GB SO-DIMM in each of its two memory slots, the computer only supports 3GB total memory.
- iMac (Late 2009), iMac (Mid 2010), and iMac (Mid 2011) have four SDRAM slots, each of which can accept a 2GB or 4GB SO-DIMM.
- These iMac models have no user-installable SDRAM slots. An Apple Authorized Service Provider (AASP) can install SDRAM in these computers.
- 27-inch iMac models introduced in 2012 through 2015 have four SDRAM slots, each of which can accept a 4GB or 8GB SO-DIMM.
- 27-inch iMac models introduced in 2017 and 2019 have four SDRAM slots, each of which can accept a 4GB, 8GB, or 16GB SO-DIMM.
- Learn more about integrated video on Intel-based Macs.
Learn more
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Learn about integrated video on Intel-based Macs
Get more information about memory and specific iMac models: