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iMac (Retina 4K, 21.5-inch, 2019) vs iMac (Retina 5K, 27-inch, 2019)

iMac (Retina 4K, 21.5-inch, 2019)1iMac (Retina 5K, 27-inch, 2019)2

Quick look

Quick look: iMac (Retina 4K, 21.5-inch, 2019) against iMac (Retina 5K, 27-inch, 2019)
FigureiMac (Retina 4K, 21.5-inch, 2019)1iMac (Retina 5K, 27-inch, 2019)2
Price£1,2493launch price£1,7493launch price
ChipCore i33.6GHz quad-core IntelCore i53.0GHz 6-core Intel
CPU4-coreCPU6-coreCPU
Memory8GBmemory, base8GBmemory, base
Storage256GBstorage, base1TBstorage, base
Display21.5-inchdisplay27-inchdisplay
Released19 March 20194Available online; Apple gave no in-store day19 March 20194Available online; Apple gave no in-store day
Security updatesNot available5Security updatesNot available5Security updates
Price
The iMac (Retina 4K, 21.5-inch, 2019) is £1,249 at launch, per Apple Newsroom (UK); the iMac (Retina 5K, 27-inch, 2019) is £1,749 at launch, per Apple Newsroom (UK).

True to scale

iMac (Retina 4K, 21.5-inch, 2019) · 528 × 450 mm frontiMac (Retina 5K, 27-inch, 2019) · 650 × 516 mm front

Front faces, from Apple’s published dimensions, drawn to one scale and superposed. Corner rounding is our drawing convention, not a measurement.

Specifications

Each figure is from the source marked by its Mac’s name unless it carries its own small number, which links to where that figure was read.

Body

Body: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple iMac (Retina 5K, 27-inch, 2019)
SpecificationiMac (Retina 4K, 21.5-inch, 2019)1iMac (Retina 5K, 27-inch, 2019)2
Dimensions450 x 528 x 175 mm516 x 650 x 203 mm
Weight5.48 kg9.42 kg
PortsTwo Thunderbolt 3 (USB-C) ports, four USB-A ports, SDXC card slot, Gigabit Ethernet (RJ-45), 3.5 mm headphone jackTwo Thunderbolt 3 (USB-C) ports, four USB 3 ports, SDXC card slot, Gigabit Ethernet (RJ-45), 3.5 mm headphone jack
Thunderbolt ports22
Thunderbolt versionThunderbolt 3Thunderbolt 3
USB-A ports44
HDMINo HDMI port.6No HDMI port.7
SD card slotYesYes
Headphone jackYesYes
KeyboardMagic KeyboardMagic Keyboard
Touch IDNo Touch ID.6No Touch ID.7

Display

Display: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple iMac (Retina 5K, 27-inch, 2019)
SpecificationiMac (Retina 4K, 21.5-inch, 2019)1iMac (Retina 5K, 27-inch, 2019)2
Display size21.5 in27 in
Resolution4096 x 23045120 x 2880
Display typeRetina 4K displayRetina 5K display
Brightness500 nits500 nits
Wide colour (P3)YesYes

Chip and memory

Chip and memory: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple iMac (Retina 5K, 27-inch, 2019)
SpecificationiMac (Retina 4K, 21.5-inch, 2019)1iMac (Retina 5K, 27-inch, 2019)2
Chip3.6GHz quad-core Intel Core i33.0GHz 6-core Intel Core i5
Apple siliconIntel processor, not Apple silicon.8Intel processor, not Apple silicon.9
CPU cores46
GraphicsRadeon Pro 555X with 2GB of GDDR5 memoryRadeon Pro 570X with 4GB of GDDR5 memory
Chip options3.6GHz quad-core Intel Core i3, 3.0GHz 6-core Intel Core i5, or 3.2GHz 6-core Intel Core i73.0GHz 6-core Intel Core i5, 3.1GHz 6-core Intel Core i5, 3.7GHz 6-core Intel Core i5, or 3.6GHz 8-core Intel Core i9
Memory (base)8GB8GB
Memory (maximum)32GB64GB
Memory options8GB, 16GB or 32GB8GB, 16GB, 32GB or 64GB
Memory upgradeable by userNo, as Apple documents10Yes, as Apple documents10
Storage (base)256GB1TB
Storage (maximum)1TB3TB
Storage options256GB SSD or 1TB Fusion Drive1TB, 2TB or 3TB Fusion Drive, or 256GB, 512GB, 1TB or 2TB SSD

Connectivity

Connectivity: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple iMac (Retina 5K, 27-inch, 2019)
SpecificationiMac (Retina 4K, 21.5-inch, 2019)1iMac (Retina 5K, 27-inch, 2019)2
Wi-Fi802.11ac Wi-Fi802.11ac Wi-Fi
Bluetooth4.24.2
Ethernet10/100/1000BASE-T Gigabit Ethernet (RJ-45)10/100/1000BASE-T Gigabit Ethernet (RJ-45)
External displays (base)22

Camera and audio

Camera and audio: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple iMac (Retina 5K, 27-inch, 2019)
SpecificationiMac (Retina 4K, 21.5-inch, 2019)1iMac (Retina 5K, 27-inch, 2019)2
CameraFaceTime HD cameraFaceTime HD camera
SpeakersStereo speakersStereo speakers
MicrophonesMicrophoneMicrophone

Platform

Platform: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple iMac (Retina 5K, 27-inch, 2019)
SpecificationiMac (Retina 4K, 21.5-inch, 2019)1iMac (Retina 5K, 27-inch, 2019)2
Shipped withmacOS Mojave11macOS Mojave11
Newest macOSmacOS Sequoia12macOS Sequoia12
Model identifieriMac19,212iMac19,112
Model year20192019

Benchmarks

Benchmarks: Apple iMac (Retina 4K, 21.5-inch, 2019) against Apple iMac (Retina 5K, 27-inch, 2019)
SpecificationiMac (Retina 4K, 21.5-inch, 2019)1iMac (Retina 5K, 27-inch, 2019)2
Geekbench 7 (CPU, single-core)1,169131,28913
Geekbench 7 (CPU, multi-core)3,336134,78013

Sources

  1. Apple Support (UK) — iMac (Retina 4K, 21.5-inch, 2019) - Technical Specifications · Default for iMac (Retina 4K, 21.5-inch, 2019) · Apple’s figure · read 15 Sep 2026

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  2. Apple Support (UK) — iMac (Retina 5K, 27-inch, 2019) - Technical Specifications · Default for iMac (Retina 5K, 27-inch, 2019) · Apple’s figure · read 15 Sep 2026

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  3. Apple Newsroom (UK) — iMac gets a 2x performance boost · Apple’s figure · read 15 Sep 2026

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  4. Apple Newsroom (UK) — iMac gets a 2x performance boost · Apple’s figure · read 22 Sep 2026

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  5. Security updates: no end date published. Checked: endoflife.date. Read 22 Sep 2026

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  6. iMac (Retina 4K, 21.5-inch, 2019): No HDMI port. No Touch ID. Checked: Apple Support (UK) — iMac (Retina 4K, 21.5-inch, 2019) - Technical Specifications. Read 9 Oct 2026

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  7. iMac (Retina 5K, 27-inch, 2019): No HDMI port. No Touch ID. Checked: Apple Support (UK) — iMac (Retina 5K, 27-inch, 2019) - Technical Specifications. Read 9 Oct 2026

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  8. iMac (Retina 4K, 21.5-inch, 2019): Intel processor, not Apple silicon. Checked: Apple Support (UK) — iMac (Retina 4K, 21.5-inch, 2019) - Technical Specifications. Read 15 Sep 2026

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  9. iMac (Retina 5K, 27-inch, 2019): Intel processor, not Apple silicon. Checked: Apple Support (UK) — iMac (Retina 5K, 27-inch, 2019) - Technical Specifications. Read 15 Sep 2026

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  10. Apple Support (UK) — Install memory in an iMac · Apple’s figure · read 18 Oct 2026

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  11. Apple Newsroom (UK) — iMac gets a 2x performance boost · Apple’s figure · read 9 Oct 2026

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  12. Apple Support (UK) — Identify your iMac model · Apple’s figure · read 15 Sep 2026

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  13. Geekbench Browser (Primate Labs) · third-party figure · read 11 Oct 2026

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Not published by Apple

iMac (Retina 4K, 21.5-inch, 2019). Apple doesn’t publish for this Mac: colours, pixel density, refresh rate, nano-texture option, GPU cores, storage upgradeable by user, maximum continuous power. Geekbench 7 Metal: the Mac chart has no Metal score for this Mac (chart read 10 Oct 2026). Pages checked: Apple Support (UK) — iMac (Retina 4K, 21.5-inch, 2019) - Technical Specifications; Apple Support (UK) — Identify your iMac model; Apple Newsroom (UK) — iMac gets a 2x performance boost, read 9 Oct 2026.

iMac (Retina 5K, 27-inch, 2019). Apple doesn’t publish for this Mac: colours, pixel density, refresh rate, nano-texture option, GPU cores, storage upgradeable by user, maximum continuous power. Geekbench 7 Metal: the Mac chart has no Metal score for this Mac (chart read 10 Oct 2026). Pages checked: Apple Support (UK) — iMac (Retina 5K, 27-inch, 2019) - Technical Specifications; Apple Support (UK) — Identify your iMac model; Apple Newsroom (UK) — iMac gets a 2x performance boost, read 9 Oct 2026.

If you own one of them

Whether to move is a different question from which is better. Each Mac has a page on it: what its successor changes (the newest Mac in its line where Apple sells one, otherwise the Mac this site treats as its replacement, which can be in another line), what it fetches and whether it still gets updates. Should I upgrade my iMac (Retina 4K, 21.5-inch, 2019)? · Should I upgrade my iMac (Retina 5K, 27-inch, 2019)?

The pairs a buyer of either Mac would also weigh. Any two Macs in the catalogue can be compared from the chooser.