Apple iMac (Retina 5K, 27-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 (Retina 5K, 27-inch, 2017) compared with iMac (Retina 5K, 27-inch, Late 2015)
AppleiMac (Retina 5K, 27-inch, 2017)AppleiMac (Retina 5K, 27-inch, Late 2015)
Overview
ReleasedJune 2017October 2015
Performance
ProcessorIntel Core i5-7500, Intel Core i5-7600, Intel Core i7-7700K or Intel Core i5-7600KIntel Core i5-6500, Intel Core i7-6700K or Intel Core i5-6600
CPU cores44
CPU threads4 or 84 or 8
GraphicsRadeon Pro 570 (4 GB VRAM), Radeon Pro 575 (4 GB VRAM) or Radeon Pro 580 (8 GB VRAM)AMD 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, 16 GB, 32 GB or 64 GB (better)8 GB, 16 GB or 32 GB
Storage256 GB to 3 TB256 GB to 3 TB
CPUQuad-core Core i5 at 3.4 GHz (Turbo Boost 3.8 GHz), 3.5 GHz (Turbo Boost 4.1 GHz) or 3.8 GHz (Turbo Boost 4.2 GHz); only the upper two bases support the 4.2 GHz Core i7 upgrade with Turbo Boost up to 4.5 GHz3.2 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.
GPURadeon Pro 570 or 575 with 4 GB VRAM, or Radeon Pro 580 with 8 GB VRAM; graphics are tied to the three base configurationsAMD 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 type2400 MHz DDR4; 8 GB standard as two 4 GB modules in four user-accessible SO-DIMM slots. Lower base configurable to 16/32 GB; upper two bases to 16/32/64 GB.1867 MHz DDR3; 8 GB standard as two 4 GB modules, configurable to 16 GB or 32 GB; four user-accessible SO-DIMM slots
Storage type570 base: 1/2 TB Fusion Drive or 256/512 GB/1 TB SSD. 575 base: 1/2/3 TB Fusion Drive or 256/512 GB/1 TB SSD. 580 base: 2/3 TB Fusion Drive or 512 GB/1/2 TB SSD.M380 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 size27″27″
Resolution5120 × 28805120 × 2880
PanelIPS LCDIPS LCD
Brightness500 nits–
Display typeLED-backlit Retina 5K display; IPS panel confirmed by EveryMac; Apple does not publish native refresh rate in this model’s specification sheetLED-backlit Retina 5K display with IPS technology and support for millions of colours
Display featuresWide colour (P3); supports one billion coloursP3 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 3 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, 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 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 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 mouseRechargeable Magic Keyboard and Magic Mouse 2; optional Magic Keyboard with Numeric Keypad and Magic Trackpad 2Rechargeable Magic Keyboard and Magic Mouse 2; optional Magic Trackpad 2 with Force Touch
Design and power
TypeAll-in-oneAll-in-one
Weight9.44 kg (better)9.54 kg
Width × depth × height650 × 203 × 516 mm650 × 203 × 516 mm
Operating systemmacOSmacOS
Size and weight detailDimensions include the stand; weight varies by configuration. A built-in VESA mount version was also 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
Noise–Apple'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
MaterialsRecyclable aluminium enclosure; arsenic-free glass and mercury-free LED backlightRecyclable aluminium enclosure; arsenic-free display glass; mercury-free LED backlight
In the boxiMac, Magic Keyboard, Magic Mouse 2, power lead and Lightning to USB cableiMac, Magic Keyboard, Magic Mouse 2, power lead and Lightning to USB cable

More comparisons