Apple iMac (Retina 4K, 21.5-inch, 2019) vs Apple iMac (Retina 5K, 27-inch, Mid 2015)

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iMac (Retina 4K, 21.5-inch, 2019) compared with iMac (Retina 5K, 27-inch, Mid 2015)

	AppleiMac (Retina 4K, 21.5-inch, 2019)	AppleiMac (Retina 5K, 27-inch, Mid 2015)
Overview
Released
Released	March 2019	May 2015
Performance
Processor
Processor	Intel Core i3-8100, Intel Core i7-8700 or Intel Core i5-8500	Intel Core i5-4590
CPU cores
CPU cores	4 or 6	4
CPU threads
CPU threads	4, 6 or 12	4
Graphics
Graphics	Radeon Pro 555X (2 GB GDDR5), Radeon Pro 560X (4 GB GDDR5) or Radeon Pro Vega 20 (4 GB HBM2)	AMD Radeon R9 M290 (2 GB GDDR5)
Memory
Memory	8 GB, 16 GB or 32 GB	8 GB, 16 GB or 32 GB
Storage
Storage	256 GB to 1 TB	256 GB to 3 TB (better)
CPU
CPU	3.6 GHz quad-core Core i3 without Turbo Boost, or 3.0 GHz six-core Core i5 with Turbo Boost up to 4.1 GHz; both configurable to 3.2 GHz six-core Core i7 with Turbo Boost up to 4.6 GHz	Fixed 3.3 GHz quad-core Intel Core i5-4590 with Turbo Boost up to 3.7 GHz; exact chip identified in Macworld and The Register's tests. Apple's configure-to-order section is headed 3.5 GHz and repeats options from the higher model; those processor options are excluded from this entry.
GPU
GPU	Radeon Pro 555X with 2 GB GDDR5 in the lower base; Radeon Pro 560X with 4 GB GDDR5 in the upper base, configurable to Radeon Pro Vega 20 with 4 GB HBM2	AMD Radeon R9 M290 with 2 GB GDDR5; the higher model's M290X and optional M295X are outside this configuration
Memory type
Memory type	8 GB standard, configurable to 16/32 GB; lower base uses 2400 MHz DDR4 and upper base 2666 MHz DDR4. Memory is not readily user-accessible.	1600 MHz DDR3; 8 GB (two 4 GB modules), configurable to 16 GB or 32 GB; four user-accessible SO-DIMM slots
Storage type
Storage type	The current Apple sheet lists 256 GB SSD or 1 TB Fusion Drive for both bases, and these are the configurations shown. Apple made SSD storage standard in August 2020. Launch reviews describe a 1 TB hard drive in the lower base and 1 TB Fusion Drive in the upper base, with larger SSD options (Macworld and TechRadar); these historical options are not flattened into the current matrix.	1 TB 7200-rpm hard drive, configurable to 3 TB hard drive, 1 TB or 3 TB Fusion Drive, or 256 GB, 512 GB or 1 TB flash storage (SSD)
Display
Screen size
Screen size	21.5″	27″
Resolution
Resolution	4096 × 2304	5120 × 2880 (better)
Panel
Panel	IPS LCD	IPS LCD
Brightness
Brightness	500 nits	–
Display type
Display type	LED-backlit Retina 4K display; IPS panel confirmed by EveryMac; Apple does not publish native refresh rate in this model’s specification sheet	27-inch Retina 5K display with IPS technology and support for millions of colours
Display features
Display features	Wide colour (P3); supports one billion colours	–
Connections
Ports
Ports	2 × Thunderbolt 3, 4 × USB-A, SD card slot, Ethernet, headphone jack	2 × Thunderbolt 2, 4 × USB-A, SD card slot, Ethernet, headphone jack
Ethernet
Ethernet	1 Gb/s	1 Gb/s
External displays
External displays	Up to 2 (better)	Up to 1
Wi-Fi
Wi-Fi	802.11ac	802.11ac
Bluetooth
Bluetooth	4.2	4.0
Camera
Camera	FaceTime HD	FaceTime HD
Back ports
Back ports	Four USB-A ports; two Thunderbolt 3 USB-C ports with DisplayPort, Thunderbolt up to 40 Gb/s and USB 3.1 Gen 2 up to 10 Gb/s; SDXC, Gigabit Ethernet and 3.5 mm headphone jack; Kensington lock slot. Thunderbolt 2, HDMI, DVI and VGA require separately sold adapters.	Four USB 3 ports, two Thunderbolt 2 ports with Mini DisplayPort output, SDXC card slot, Gigabit Ethernet, headphone and optical digital audio output; Kensington lock slot. DVI, VGA and dual-link DVI require separately sold adapters.
External displays
External displays	Built-in display at full 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 colours	Built-in display at native resolution alongside one external display up to 3840 × 2160; extended desktop and video mirroring
Speakers
Speakers	Stereo speakers	Stereo speakers; supports Apple iPhone headset with microphone
Microphones
Microphones	Built-in microphone	Dual microphones
Keyboard and mouse
Keyboard and mouse	Rechargeable Magic Keyboard and Magic Mouse 2; optional Magic Keyboard with Numeric Keypad and Magic Trackpad 2	Apple Wireless Keyboard and Magic Mouse; optional Magic Trackpad
Design and power
Type
Type	All-in-one	All-in-one
Weight
Weight	5.48 kg (better)	9.54 kg
Width × depth × height
Width × depth × height	528 × 175 × 450 mm	650 × 203 × 516 mm
Operating system
Operating system	macOS	macOS
Size and weight detail
Size and weight detail	Dimensions include the stand; current Apple sheet lists 5.48 kg and warns that weight varies by configuration. Launch reviews tested heavier hard-drive/Fusion configurations. A built-in VESA mount version was also available.	Dimensions include the stand; weight varies by configuration and manufacturing process. A built-in VESA mount version was also available.
Power supply
Power supply	100–240 V AC, 50–60 Hz, single phase	100–240 V AC, 50–60 Hz, single phase
Materials
Materials	Recyclable aluminium enclosure; arsenic-free glass and mercury-free LED backlight	Recyclable aluminium and glass enclosure; arsenic-free display glass and mercury-free LED backlight
In the box
In the box	iMac, Magic Keyboard, Magic Mouse 2, power lead and Lightning to USB cable	iMac with Retina 5K display, Apple Wireless Keyboard, Magic Mouse and power lead; OS X Yosemite