Only the differences are shown. 18 specs stay the same.
+8you gain
−0you give up
iMac (Retina 4K, 21.5-inch, 2019) came out in March 2019. iMac (Retina 5K, 27-inch, 2020) came out in August 2020, over 1 year later. iMac (Retina 4K, 21.5-inch, 2019) stopped getting new macOS versions at macOS Sequoia 15. iMac (Retina 5K, 27-inch, 2020) stopped getting new macOS versions at macOS Tahoe 26.
Note on iMac (Retina 4K, 21.5-inch, 2019): Most storage you can order is a 1TB Fusion Drive. Price from Apple Newsroom (March 2019).
Note on iMac (Retina 5K, 27-inch, 2020): Not listed as vintage or obsolete on Apple's page when checked.
Updates & AI
macOS Sequoia 15 → macOS Tahoe 26
Repaired by Apple
Chip & memory
3.6GHz quad-core Intel Core i3 → 3.1GHz 6-core 10th-generation Intel Core i5
6 CPU cores, 128 GB max memory, 8 TB max storage
Screen
Retina 4K → Retina 5K
27 in screen, 5120x2880, nano-texture option
Ports & charging
Gigabit → Gigabit
Bluetooth 5.0
Price check
iMac (Retina 5K, 27-inch, 2020) launched at $1,799
Not currently sold refurbished by Apple.
All 18 differences
Updates & AI2 gains
Latest macOS
macOS Sequoia 15›macOS Tahoe 26
What does this mean?
macOS is the software that runs the Mac: the desktop, Finder, the built-in apps, the settings and the security protection. Apple releases a new version every autumn.
A Mac on the newest macOS gets new features and regular security fixes. A Mac stuck on an older version keeps working, but over time apps start requiring a newer macOS, and security fixes stop. Apple has said macOS Tahoe 26 is the last version for Macs with Intel processors.
Matters most if: You use work, school or banking apps that need a recent macOS.
Apple repair support
Vintage: limited repairs›Repaired by Apple
What does this mean?
Apple counts from when it stopped selling the model, not from its release date. Vintage: Apple stopped selling it 5 to 7 years ago; repairs only while parts last. Obsolete: over 7 years ago; Apple no longer repairs it.
Checked against Apple's vintage and obsolete products list on 2026-10-11. Mac laptops may still get battery-only repairs for up to 10 years after Apple stopped selling them, if parts are available.
Apple Intelligence
No (same on both)
What does this mean?
Apple Intelligence is Apple's set of AI features: writing help that rewrites or proofreads your text, summaries of long emails and notifications, Clean Up in Photos, and the new Siri AI.
On Mac it needs Apple silicon, the M1 chip or later. Macs with Intel processors cannot get it. Which features you see also depends on your country and language.
Price1 change
Price check
iMac (Retina 5K, 27-inch, 2020) — launched at $1,799
- Used on eBay
- Refurbished on Back Market
- Apple does not currently sell this model refurbished
What your iMac (Retina 4K, 21.5-inch, 2019) sells for
- Apple Trade In estimate
- Sold listings on eBay
eBay may ask you to sign in to see sold prices.
Links open in a new tab. Prices are set by each seller and change daily.
Launch price (US)
$1,299›$1,799+$500
What does this mean?
The price Apple charged in the US on launch day for the lowest configuration, before tax.
This is not what the Mac costs today. More memory, storage or a faster chip cost extra. Older models drop in price over time, so check the used and refurbished links for current prices.
Chip & memory3 gains · 1 change
Chip options: iMac (Retina 4K, 21.5-inch, 2019)
- 3.6GHz quad-core Intel Core i3
- 3.0GHz 6-core Intel Core i5
- 3.2GHz 6-core Intel Core i7
Chip options: iMac (Retina 5K, 27-inch, 2020)
- 3.1GHz 6-core 10th-generation Intel Core i5
- 3.3GHz 6-core 10th-generation Intel Core i5
- 3.8GHz 8-core 10th-generation Intel Core i7
- 3.6GHz 10-core 10th-generation Intel Core i9
Chip
3.6GHz quad-core Intel Core i3›3.1GHz 6-core 10th-generation Intel Core i5
What does this mean?
The chip is the Mac's brain. Since late 2020 Apple uses its own chips (Apple silicon: M1, M2 and later). Before that, MacBooks used Intel processors.
Apple silicon Macs run cooler and much longer on battery than Intel MacBooks, and can run many iPhone and iPad apps. Intel Macs can run Windows directly with Boot Camp; Apple silicon Macs cannot.
Matters most if: You need Windows, or you want the longest battery life.
CPU cores
4›6
What does this mean?
The CPU is the part of the chip that runs your apps. More cores means it can work on more things at the same time.
More cores help most when exporting video, compiling code or running many apps at once. For browsing and email, the difference is small. Cores are only comparable within the same family: one Apple silicon core and one Intel core do not do the same amount of work.
Memory (most you can order)
32 GB›128 GB
What does this mean?
The most memory you could order from Apple for this model.
Only matters if you plan to buy a high-end configuration, for example for large video projects or software development.
Storage (most you can order)
1 TB›8 TB
What does this mean?
The most storage you could order from Apple for this model.
Only matters if you need to keep very large files on the Mac itself rather than on an external drive.
GPU cores
Not published by Apple (same on both)
What does this mean?
The GPU handles graphics: what you see on screen, games, and video and photo effects. Apple lists GPU cores for its own chips.
More GPU cores make games, 3D work and video editing smoother. "Not published by Apple" means the Mac uses Intel or AMD graphics, which Apple does not describe in cores.
Neural Engine cores
None (Intel) (same on both)
What does this mean?
The Neural Engine is a part of Apple silicon built for machine learning tasks, such as recognizing faces and text in photos.
It speeds up features like Live Text, photo search, voice dictation and Apple Intelligence, while using little battery. Intel Macs do not have one.
Memory type
DDR4 (same on both)
What does this mean?
Memory (RAM) is the working space for open apps and files. Apple silicon uses unified memory: one pool shared by the CPU, GPU and Neural Engine. Intel Macs list a memory type such as DDR4.
Unified memory is part of the chip, so it cannot be added later. Apple's spec pages list user-accessible memory slots only for the 27-inch Intel iMac and the 2019 Mac Pro.
Memory (base)
8 GB (same on both)
What does this mean?
How much memory (RAM) the cheapest configuration comes with, in gigabytes (GB).
More memory lets you keep more apps and browser tabs open without slowing down. 8 GB is enough for browsing and documents; 16 GB or more helps with photo editing, video and many apps at once. On Apple silicon Macs memory cannot be added later.
Matters most if: You keep many apps or tabs open, or edit photos and video.
Storage (base)
256 GB (same on both)
What does this mean?
Storage is where your files, photos and apps are kept. This is the amount in the cheapest configuration. 1 TB (terabyte) is 1,024 GB. Some older iMacs came with a hard drive or Fusion Drive instead of an SSD; the notes say when.
A desktop Mac can keep an external drive plugged in all the time, which makes a smaller internal drive easier to live with. Photo libraries and video fill storage fastest.
Screen1 gain · 3 changes
Screen size
21.5 in›27 in
What does this mean?
Screen size measured corner to corner, in inches. One inch is 2.54 cm. Only iMac has a built-in screen; Mac mini, Mac Studio and Mac Pro use a separate display. Apple lists the 24-inch iMac's actual diagonal as 23.5 inches.
A bigger screen fits more windows side by side, and on an iMac it also sets how much room it takes on your desk.
Resolution
4096x2304›5120x2880
What does this mean?
How many dots (pixels) make up the screen, across by down.
More pixels on the same size of screen make text and photos look sharper. macOS scales everything so text stays a comfortable size.
Display
Retina 4K›Retina 5K
What does this mean?
Apple's name for the screen. Retina means sharp enough that you cannot see the dots at a normal distance. Liquid Retina is Apple's name for its newer LCD screens with rounded corners. Liquid Retina XDR uses mini-LED lighting for much higher brightness and contrast.
XDR screens show HDR video and photos far brighter and with deeper blacks than Retina and Liquid Retina screens.
Nano-texture display option
GainWhat does this mean?
Apple offers an optional nano-texture screen: the glass surface is etched with a pattern too small to see, which scatters reflected light.
Reflections from windows and lights are greatly reduced, while the picture stays clear. It costs extra, and the screen should be cleaned only with the special cloth Apple includes.
Matters most if: You work near windows, outdoors, or under bright office lights.
Screen type
Not published by Apple (same on both)
What does this mean?
LCD screens use one light behind the whole screen. Mini-LED screens use thousands of tiny lights behind the screen, each lighting a small area that can dim on its own.
Mini-LED shows deeper blacks and much brighter highlights, which you notice most in HDR films and photo editing. For documents and browsing, both look good.
120 Hz ProMotion
No (same on both)
What does this mean?
Hz (hertz) means times per second. A standard MacBook screen redraws 60 times per second (60 Hz). ProMotion goes up to 120 times per second (120 Hz) and slows down when nothing moves, to save battery.
Scrolling through pages, moving windows and animations look noticeably smoother.
Brightness (SDR)
500 nits (same on both)
What does this mean?
Nits measure brightness. This is the brightness Apple lists for everyday (SDR) content such as documents and websites, not the higher peak for HDR video.
A brighter screen is easier to read near a window or outdoors. 500 nits works well indoors. "Not published by Apple" means Apple's spec page for that model does not give a figure.
Camera1 change
Camera
FaceTime HD camera›1080p FaceTime HD camera
What does this mean?
The camera above the screen used for video calls. 480p, 720p and 1080p describe video sharpness (more lines of detail is sharper). 12MP Center Stage is a higher-resolution wide camera.
A 1080p camera makes you look noticeably sharper in calls than a 720p one. The 12MP Center Stage camera can also follow you as you move and show your desk with Desk View.
Matters most if: You make a lot of video calls.
Center Stage
No (same on both)
What does this mean?
Center Stage uses the wide camera to keep you in frame during video calls.
If you lean back or shift in your seat, the picture follows you. When someone joins you, it widens to fit both of you.
Ports & charging2 gains
Ethernet
Gigabit Ethernet›Gigabit Ethernet (10Gb option)
What does this mean?
Ethernet is a wired network connection: a cable from the Mac to your router. Gigabit Ethernet carries up to 1 Gb/s (gigabit per second), 2.5Gb Ethernet up to 2.5 Gb/s and 10Gb Ethernet up to 10 Gb/s. "10Gb option" means Apple sold a 10Gb port as an option when you ordered; "optional" means Ethernet itself was an option.
A cable is steadier than Wi-Fi for video calls and large downloads. The faster speeds only help if your router, switch or network drive is just as fast.
Matters most if: You copy large files to and from a network drive or other computers.
Bluetooth
Bluetooth 4.2›Bluetooth 5.0
What does this mean?
Bluetooth connects wireless headphones, mice, keyboards and game controllers. Newer versions have more range and use less power.
Most accessories work with any of these versions. Newer versions mainly help with range and connection stability.
Ports
2x Thunderbolt 3 (USB-C), 4x USB-A, SDXC card slot, 3.5 mm headphone jack (same on both)
What does this mean?
The sockets on the Mac, front and back together. Each row shows one port gained or lost. Ethernet has its own row.
Built-in HDMI and an SD card slot mean fewer adapters when you connect a TV or projector or copy photos from a camera. With fewer ports you rely more on USB-C hubs and adapters.
Matters most if: You connect displays, cameras or many accessories.
Front ports
Not listed separately by Apple (same on both)
What does this mean?
The ports on the front of the Mac, which you can reach without turning it around. They are also counted in Ports.
Handy for things you plug in and out often, such as headphones, a USB stick or an SD card from a camera. "Not listed separately by Apple" means Apple's spec page lists the ports without saying which are on the front.
Thunderbolt version
Thunderbolt 3 (same on both)
What does this mean?
Thunderbolt is a fast connection that uses the USB-C plug (Thunderbolt 2 used an older, smaller plug). Gb/s is gigabits per second. Thunderbolt 2 goes up to 20 Gb/s, Thunderbolt 3 and 4 up to 40 Gb/s, and Thunderbolt 5 up to 120 Gb/s.
Faster Thunderbolt matters for external SSDs, docks and high-resolution displays. For charging, keyboards and mice, every version works the same.
External displays (most)
2 external displays (same on both)
What does this mean?
The most separate displays you can connect at the same time, as Apple's spec page lists it. On an iMac this is on top of its own screen.
Very high resolutions or refresh rates can lower the number; Apple's spec page lists the exact combinations. More display support helps when you spread your work across several screens.
Matters most if: You want two or more monitors on your desk.
Wi-Fi
Wi-Fi 5 (same on both)
What does this mean?
Wi-Fi generations. Each new one handles more devices at once and higher speeds: Wi-Fi 5 (2014), Wi-Fi 6 (2019), Wi-Fi 6E adds a new, less crowded radio band, Wi-Fi 7 is the newest.
You only get the extra speed if your router supports the same generation. With an older router, the difference is small.
Maximum continuous power
Not published by Apple (same on both)
Design4 changes
Weight
5.48 kg›8.92 kg
What does this mean?
Weight in kilograms. 1 kg is about 2.2 pounds.
For a desktop Mac, weight matters when you move it or take it between places.
Height
45 cm›51.6 cm
Width
52.8 cm›65 cm
Depth
17.5 cm›20.3 cm
Speakers
Stereo speakers (same on both)
What does this mean?
How Apple describes the Mac's speakers on its spec page. Apple's wording varies between models. We show it exactly as Apple lists it.
Apple lists a single built-in speaker for Mac mini, Mac Studio and Mac Pro, so for music and films you will want speakers or headphones. Systems with force-cancelling woofers give fuller sound with more bass.
What's new
RSS feedAdded Mac mini, iMac, Mac Studio and Mac Pro
33 desktop Macs from 2017 onward, checked against Apple's tech specs pages, in one Mac section with the laptops, so you can compare a Mac mini with a MacBook Air. Specs a model does not have, such as a screen on Mac mini, show as Not applicable.
Added MacBook, MacBook Air, MacBook Pro and MacBook Neo
45 Mac laptops from 2016 onward, checked against Apple's tech specs pages. Older models appear on the timeline and open for comparison once they are checked. Switch to Mac at the top of the home page.
Added every iPad since 2010
45 iPad, iPad mini, iPad Air and iPad Pro models, checked against Apple's tech specs pages. Switch between iPhone and iPad at the top of the home page.