Apple iMac (21.5-inch, 2017) vs Apple iMac (Retina 5K, 27-inch, Late 2015)

Every spec side by side, from each maker's published figures.

Better figure, where one is clearly better

iMac (21.5-inch, 2017) compared with iMac (Retina 5K, 27-inch, Late 2015)
AppleiMac (21.5-inch, 2017)AppleiMac (Retina 5K, 27-inch, Late 2015)
Overview
ReleasedJune 2017October 2015
Performance
ProcessorIntel Core i5-7360UIntel Core i5-6500, Intel Core i7-6700K or Intel Core i5-6600
CPU cores24
CPU threads44 or 8
GraphicsIntel Iris Plus Graphics 640AMD Radeon R9 M380 (2 GB GDDR5), AMD Radeon R9 M390 (2 GB GDDR5), AMD Radeon R9 M395 (2 GB GDDR5) or AMD Radeon R9 M395X (4 GB GDDR5)
Memory8 GB or 16 GB8 GB, 16 GB or 32 GB (better)
Storage256 GB to 1 TB256 GB to 3 TB (better)
CPU2.3 GHz dual-core Intel Core i5 with Turbo Boost up to 3.6 GHz; Geekbench identifies the exact processor as Core i5-7360U3.2 GHz quad-core Core i5 with Turbo Boost up to 3.6 GHz in the M380 and M390 models; 3.3 GHz quad-core Core i5 with Turbo Boost up to 3.9 GHz in the M395 model. Only the M390 and M395 bases support the 4.0 GHz Core i7 upgrade, with Turbo Boost up to 4.2 GHz.
GPUIntel Iris Plus Graphics 640; no discrete graphics optionAMD Radeon R9 M380 or M390 with 2 GB GDDR5; M395 with 2 GB GDDR5 in the upper base, configurable to M395X with 4 GB GDDR5 only in that base
Memory type8 GB of 2133 MHz DDR4, configurable to 16 GB1867 MHz DDR3; 8 GB standard as two 4 GB modules, configurable to 16 GB or 32 GB; four user-accessible SO-DIMM slots
Storage type1 TB 5400-rpm hard drive, configurable to 1 TB Fusion Drive or 256 GB SSDM380 base: 1 TB 7200-rpm hard drive, 1/2/3 TB Fusion Drive or 256/512 GB SSD. M390 base: 1/2/3 TB Fusion Drive or 256/512 GB/1 TB SSD. M395 base: 2/3 TB Fusion Drive or 256/512 GB/1 TB SSD. The 1 TB Fusion Drive has 24 GB of flash; 2/3 TB Fusion Drives have 128 GB.
Display
Screen size21.5″27″
Resolution1920 × 10805120 × 2880 (better)
Panel–IPS LCD
Display type21.5-inch LED-backlit display; 1920 × 1080 with support for millions of colours. Apple does not identify the panel technology, native refresh rate or brightness in its specification sheet; Retina model display figures do not apply.LED-backlit Retina 5K display with IPS technology and support for millions of colours
Display features–P3 colour gamut; Apple does not publish brightness or refresh rate in this model's specification sheet
Connections
Ports2 × Thunderbolt 3, 4 × USB-A, SD card slot, Ethernet, headphone jack2 × Thunderbolt 2, 4 × USB-A, SD card slot, Ethernet, headphone jack
Ethernet1 Gb/s1 Gb/s
External displaysUp to 2Up to 2
Wi-Fi802.11ac802.11ac
Bluetooth4.24.0
CameraFaceTime HDFaceTime HD
Back portsFour USB-A ports, two Thunderbolt 3 (USB-C) ports, SDXC card slot, Gigabit Ethernet, 3.5 mm headphone jack and Kensington lock slot. Thunderbolt 3 supports DisplayPort, up to 40 Gb/s Thunderbolt and up to 10 Gb/s USB 3.1 Gen 2; Thunderbolt 2, HDMI, DVI and VGA require adapters.Four USB 3 ports, two Thunderbolt 2 ports with Mini DisplayPort output, SDXC card slot, Gigabit Ethernet, 3.5 mm headphone and optical digital audio output; Kensington lock slot. HDMI, DVI, VGA and dual-link DVI require separately sold adapters.
External displaysBuilt-in display at native resolution alongside one 5120 × 2880 display at 60 Hz with one billion colours, two 3840 × 2160 displays at 60 Hz with one billion colours, or two 4096 × 2304 displays at 60 Hz with millions of coloursBuilt-in display at full native resolution alongside up to two 4096 × 2160 displays, or one 5120 × 2880 dual-cable display; extended desktop and video mirroring
SpeakersStereo speakers; supports Apple iPhone headset with microphoneStereo speakers; supports Apple iPhone headset with microphone
MicrophonesBuilt-in microphoneDual microphones
Keyboard and mouseMagic Keyboard, Magic Mouse, Lightning to USB cable and polishing cloth; configurable with Magic Keyboard with Numeric Keypad or Magic TrackpadRechargeable Magic Keyboard and Magic Mouse 2; optional Magic Trackpad 2 with Force Touch
Design and power
TypeAll-in-oneAll-in-one
Weight5.44 kg (better)9.54 kg
Width × depth × height528 × 175 × 450 mm650 × 203 × 516 mm
Operating systemmacOSmacOS
Size and weight detailDimensions include the stand; weight varies by configuration and manufacturing process. A built-in VESA mount version was available.Dimensions include the stand; weight varies by configuration. A built-in VESA mount version was also available.
Power supply100–240 V AC, 50–60 Hz, single phase100–240 V AC, 50–60 Hz, single phase
NoiseApple reports operator-position sound pressure of 11 dB at idle and during wireless web, and 12 dB during hard-drive seek, tested on the Core i5 with 8 GB memory and 1 TB hard driveApple's 3.3 GHz Core i5, 8 GB, 2 TB Fusion Drive and Radeon M395 test configuration: operator-position sound pressure 15.5 dB at idle, wireless web and hard-drive seek
MaterialsAluminium enclosure; arsenic-free display glass; mercury-, BFR- and beryllium-free with regional exceptions for PVC-free power leadsRecyclable aluminium enclosure; arsenic-free display glass; mercury-free LED backlight
In the boxiMac, Magic Keyboard, Magic Mouse, Lightning to USB cable, polishing cloth and power lead. Apple's current support page describes the later macOS Big Sur release.iMac, Magic Keyboard, Magic Mouse 2, power lead and Lightning to USB cable

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