Apple iMac (21.5-inch, 2017) vs Apple iMac (Retina 4K, 21.5-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 4K, 21.5-inch, Late 2015)
AppleiMac (21.5-inch, 2017)AppleiMac (Retina 4K, 21.5-inch, Late 2015)
Overview
ReleasedJune 2017October 2015
Performance
ProcessorIntel Core i5-7360UIntel Core i5-5675R or Intel Core i7-5775R
CPU cores24
CPU threads4–
GraphicsIntel Iris Plus Graphics 640Intel Iris Pro Graphics 6200
Memory8 GB or 16 GB8 GB or 16 GB
Storage256 GB to 1 TB256 GB to 2 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 i5-7360U3.1 GHz quad-core Core i5 with Turbo Boost up to 3.6 GHz; configurable to 3.3 GHz quad-core Core i7 with Turbo Boost up to 3.8 GHz
GPUIntel Iris Plus Graphics 640; no discrete graphics option–
Memory type8 GB of 2133 MHz DDR4, configurable to 16 GB1867 MHz LPDDR3 onboard memory; 8 GB standard, configurable to 16 GB at purchase
Storage type1 TB 5400-rpm hard drive, configurable to 1 TB Fusion Drive or 256 GB SSD1 TB 5400-rpm hard drive; optional 1 TB or 2 TB Fusion Drive, or 256 GB or 512 GB SSD. The 1 TB Fusion Drive combines a hard drive with 24 GB of flash; the 2 TB version has 128 GB of flash.
Display
Screen size21.5″21.5″
Resolution1920 × 10804096 × 2304 (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 4K 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 2 (better)Up to 1
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 one external display up to 4096 × 2304; 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)5.68 kg
Width × depth × height528 × 175 × 450 mm528 × 175 × 450 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 3.1 GHz Core i5, 8 GB, 1 TB hard-drive test configuration: operator-position sound pressure 11 dB at idle and wireless web, 11.5 dB during 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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