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iMac (24-inch, M1, 2021) vs iMac (Retina 5K, 27-inch, 2020)

iMac (24-inch, M1, 2021)1iMac (Retina 5K, 27-inch, 2020)2

Quick look

Quick look: iMac M1 against iMac
FigureiMac M11iMac2
Price£1,2493launch price£1,7994launch price
ChipM1chipCore i53.1GHz 6-core 10th-generation Intel
CPU8-coreCPU6-coreCPU
GPU7-coreGPUNot available5GPU
Memory8GBunified memory, base8GBmemory, base
Storage256GBstorage, base256GBstorage, base
Display24-inchdisplay27-inchdisplay
ReleasedMay 20216Release date, month onlyOrderable online from 30 April 2021.4 August 20207Available online; Apple gave no in-store day
Security updatesNot available8Security updatesNot available8Security updates
Price
The iMac M1 is £1,249 at launch, per Apple Newsroom (UK); the iMac is £1,799 at launch, per Apple Newsroom (UK).

True to scale

iMac (24-inch, M1, 2021) · 547 × 461 mm frontiMac (Retina 5K, 27-inch, 2020) · 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 (24-inch, M1, 2021) against Apple iMac (Retina 5K, 27-inch, 2020)
SpecificationiMac M11iMac2
Dimensions461 x 547 x 147 mm516 x 650 x 203 mm
Weight4.46 kg8.92 kg
ColoursBlue, Green, Pink, Silver9Not available5
PortsTwo Thunderbolt / USB 4 ports, 3.5mm headphone jackTwo Thunderbolt 3 (USB-C) ports, four USB-A ports, SDXC card slot (UHS-II), Gigabit Ethernet (RJ-45), 3.5 mm headphone jack
Thunderbolt ports22
Thunderbolt versionThunderbolt 3Thunderbolt 3
USB-A portsNo USB-A ports.104
HDMINo HDMI port.11No HDMI port.12
SD card slotNo SD card slot.11Yes
Headphone jackYesYes
KeyboardMagic KeyboardMagic Keyboard
Touch IDNo Touch ID.10No Touch ID.12

Display

Display: Apple iMac (24-inch, M1, 2021) against Apple iMac (Retina 5K, 27-inch, 2020)
SpecificationiMac M11iMac2
Display size24 in27 in
Resolution4480 x 25205120 x 2880
Pixel density218 ppiNot available5
Display type4.5K Retina display5K Retina display
Brightness500 nits500 nits
Wide colour (P3)YesYes
Nano-texture optionNo nano-texture display option.11Yes

Chip and memory

Chip and memory: Apple iMac (24-inch, M1, 2021) against Apple iMac (Retina 5K, 27-inch, 2020)
SpecificationiMac M11iMac2
ChipApple M1 chip3.1GHz 6-core 10th-generation Intel Core i5
Apple siliconYesIntel processor, not Apple silicon.13
CPU cores86
Performance cores4Not available14
Efficiency cores4Not available14
GPU cores7Not available5
Graphics7-core GPU, 8-core GPU15AMD Radeon Pro 5300 with 4GB of GDDR6 memory
Neural Engine cores16Not available16
Chip optionsM1 with 8-core CPU and 7-core GPU or 8-core GPU3.1GHz 6-core Intel Core i5, 3.3GHz 6-core Intel Core i5, 3.8GHz 8-core Intel Core i7, or 3.6GHz 10-core Intel Core i9
Memory (base)8GB8GB
Memory (maximum)16GB128GB
Memory options8GB or 16GB8GB, 16GB, 32GB, 64GB or 128GB
Memory upgradeable by userNo, as Apple documents17Yes, as Apple documents17
Storage (base)256GB256GB
Storage (maximum)2TB8TB
Storage options256GB, 512GB, 1TB or 2TB256GB, 512GB, 1TB, 2TB, 4TB or 8TB SSD

Battery and power

Battery and power: Apple iMac (24-inch, M1, 2021) against Apple iMac (Retina 5K, 27-inch, 2020)
SpecificationiMac M11iMac2
Included power adapter143 WNot available18

Connectivity

Connectivity: Apple iMac (24-inch, M1, 2021) against Apple iMac (Retina 5K, 27-inch, 2020)
SpecificationiMac M11iMac2
Wi-Fi802.11ax Wi-Fi 6802.11ac Wi-Fi
Bluetooth5.05.0
EthernetGigabit Ethernet configurable1910/100/1000BASE-T Gigabit Ethernet (RJ-45); configurable to 10Gb Ethernet
External displays (base)12

Camera and audio

Camera and audio: Apple iMac (24-inch, M1, 2021) against Apple iMac (Retina 5K, 27-inch, 2020)
SpecificationiMac M11iMac2
Camera1080p FaceTime HD camera1080p FaceTime HD camera
SpeakersHigh-fidelity six-speaker system with force-cancelling woofersStereo speakers
MicrophonesStudio-quality three-mic array with high signal-to-noise ratio and directional beamformingStudio-quality three-mic array with high signal-to-noise ratio and directional beamforming

Platform

Platform: Apple iMac (24-inch, M1, 2021) against Apple iMac (Retina 5K, 27-inch, 2020)
SpecificationiMac M11iMac2
Newest macOSmacOS 27 Golden Gate20macOS Tahoe 2621
Model identifieriMac21,222iMac20,1 or iMac20,223
Model year20212020

Benchmarks

Benchmarks: Apple iMac (24-inch, M1, 2021) against Apple iMac (Retina 5K, 27-inch, 2020)
SpecificationiMac M11iMac2
Geekbench 7 (CPU, single-core)2,168241,45524
Geekbench 7 (CPU, multi-core)8,365246,31924

Sources

  1. Apple Support (UK) — iMac (24-inch, M1, 2021) - Technical Specifications · Default for iMac M1 · Apple’s figure · read 15 Sep 2026

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  2. Apple Support (UK) — iMac (Retina 5K, 27-inch, 2020) - Technical Specifications · Default for iMac · Apple’s figure · read 15 Sep 2026

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  3. Apple Newsroom (UK) — iMac features all-new design in vibrant colours, M1 chip, and 4.5K Retina display · Apple’s figure · read 15 Sep 2026

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  4. Apple Newsroom (UK) — 27-inch iMac gets a major update · Apple’s figure · read 15 Sep 2026

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  5. Not published by Apple. Pages checked: Apple Support (UK) — iMac (Retina 5K, 27-inch, 2020) - Technical Specifications; Apple Support (UK) — Identify your iMac model; Apple Newsroom (UK) — 27-inch iMac gets a major update. Read 9 Oct 2026

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  6. Apple Newsroom (UK) — iMac features all-new design in vibrant colours, M1 chip, and 4.5K Retina display · Apple’s figure · read 3 Oct 2026

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  7. Apple Newsroom (UK) — 27-inch iMac gets a major update · Apple’s figure · read 22 Sep 2026

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

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  9. Apple Support (UK) — Identify your iMac model · Apple’s figure · read 2 Oct 2026

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  10. iMac (24-inch, M1, 2021): No USB-A ports. No Touch ID. Checked: Apple Support (UK) — iMac (24-inch, M1, 2021) - Technical Specifications. Read 15 Sep 2026

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  11. iMac (24-inch, M1, 2021): No HDMI port. No SD card slot. No nano-texture display option. Checked: Apple Support (UK) — iMac (24-inch, M1, 2021) - Technical Specifications. Read 9 Oct 2026

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  12. iMac (Retina 5K, 27-inch, 2020): No HDMI port. No Touch ID. Checked: Apple Support (UK) — iMac (Retina 5K, 27-inch, 2020) - Technical Specifications. Read 9 Oct 2026

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  13. iMac (Retina 5K, 27-inch, 2020): Intel processor, not Apple silicon. Checked: Apple Support (UK) — iMac (Retina 5K, 27-inch, 2020) - Technical Specifications. Read 15 Sep 2026

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  14. Doesn’t apply: this is an Intel processor, and Apple lists a total core count only

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  15. Apple Support (UK) — iMac (24-inch, M1, 2021) - Technical Specifications · Apple’s figure · read 9 Oct 2026

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  16. Doesn’t apply: Apple silicon feature; this Mac has an Intel processor

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

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  18. Doesn’t apply: internal power supply, no power adapter in the box

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  19. Apple Support (UK) — iMac (24-inch, M1, 2021) - Technical Specifications · Apple’s figure · read 11 Oct 2026

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  20. Apple Support (UK) — macOS 27 Golden Gate is compatible with these computers · Apple’s figure · read 22 Sep 2026

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  21. Apple Support (UK) — macOS Tahoe 26 is compatible with these computers · Apple’s figure · read 22 Sep 2026

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  22. Apple Support (UK) — Identify your iMac model · Apple’s figure · read 10 Oct 2026

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

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

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Not published by Apple

iMac M1. Apple doesn’t publish for this Mac: refresh rate, memory bandwidth, storage upgradeable by user, media engine, maximum continuous power, the macOS it shipped with. Geekbench 7 Metal: the Mac chart row for this Mac does not state its GPU core count, so no Metal score is shown (chart read 10 Oct 2026). Pages checked: Apple Support (UK) — iMac (24-inch, M1, 2021) - Technical Specifications; Apple Support (UK) — Identify your iMac model; Apple Newsroom (UK) — iMac features all-new design in vibrant colours, M1 chip, and 4.5K Retina display, read 9 Oct 2026.

iMac. Apple doesn’t publish for this Mac: refresh rate, storage upgradeable by user, maximum continuous power, the macOS it shipped with. 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, 2020) - Technical Specifications; Apple Support (UK) — Identify your iMac model; Apple Newsroom (UK) — 27-inch iMac gets a major update, 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 M1 (24-inch, 2021)? · Should I upgrade my iMac (Retina 5K, 27-inch, 2020)?

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