Although only $200 separated the purchase price of the base model Mid-2017 1080p iMac versus the 4K Mid-2017 iMac, the differences inside couldn’t be more drastic. On the surface and on the outside they look to be the very same machine.. until you start tearing one apart and realize how much more upgradeable the 4K variant is. This 4K iMac has a socketed CPU, a SATA 3.0 port, two memory slots for PC4-19200s DDR4-2400T RAM, an NVME style PCIe x4 SSD blade slot, and an AirPort card slot which appears to also be of a PCIe interface. This iMac also uses slightly faster DDR4 over its 1080p counterpart, at 2400 MHz versus the 2133 MHz PC4-17000 spec.

Unfortunately, however – the GPU is soldered onto the logic board like every iMac after the Late 2011 model. It’s unknown if a better GPU can be fitted into one of these but it may be assumed you could swap a Radeon Pro 555 and it’s corresponding board components out with a Radeon Pro 560 through soldering. This theory remains untested.

By the way.. there was no 2018 iMac refresh, which meant the 2017 models stuck around for nearly 2 years until the 2019 models came out. For the 1080p non-retina model, it was the end of the line: that one stuck around until October 29th 2021 – a full year and some change after Apple Silicon Macs were announced!

You also get a few minor upgrades over the Late 2015 4K 21.5″, too. Namely: a bump up to Bluetooth version 4.2, the addition of 2x USB-C style Thunderbolt 3 ports, which come with USB 3.1. Bluetooth 4.2 introduces better file transfer speeds claimed up to 2.5x over previous versions, and better user privacy through random address generation.

For a performance boost this model offers a 1 TB Fusion Drive which is a hard drive combined up with a 24 GB SSD in this particular model. The Fusion Drive ships standard with the 3.4 GHz i5-7500 option, but must be added-on if you purchased the base model. You could also option it up to a 1 TB SSD for best performance results, if and only if you got the i5-7500 or i7-7700. Fusion Drives are a newer technology that was phased away eventually in favor of a full-on SSD in all Macs, and a failure of either the SSD or HDD inside the Fusion Drive would be catastrophic to the entire drive. The cool part about having a Fusion Drive is it keeps track of your work patterns and will move files, data, and applications to the SSD or back to the hard drive based on that information – with full transparency.

Some Quirks

Although the base model was configurable to 16 GB of RAM through Apple’s website at time of purchase, many users found they could take 32 GB of RAM using two 16 GB DDR4 sticks. Intel’s website lists the i5-7400/7500 as well as the i7-7700 as being compatible with up to 64 GB RAM, and OWC sells a 64 GB RAM (2x 32GB) kit on their website for $129.99 in Dec 2024. Moreover, all 4K iMacs have Intel UHD graphics built-into the CPU but it doesn’t reflect in system profiler or is used.

What You Need to Know

• These iMacs shipped with 8 GB of RAM standard which is fine for basic tasks, but is increasingly impractical these days. For a serious speed boost, opt for 16 GB of RAM or more, and an SSD over the Fusion Drive or Hard Drive.
• Most base models shipped with a 1 TB 5400 RPM SATA 3.0 (6Gb/s) hard drive. Wasn’t fast in 2017, let alone today.
• The base i5-7400 3.0 chip supports 64 GB of RAM according to intel, but Apple claims it can only be configured up to 16 GB.
• The optional 3.4 i5-7500 and 3.6 i7-7700 also support 64 GB of RAM according to intel, but Apple claims it can only be configured up to 32 GB.
• Yes, it is possible to put an i7-7700K into one of these, a CPU option not offered by Apple. Users who have performed this upgrade claim it throttles under full load.

Unsupported macOS

Although it is not officially supported, the 21.5″ 4K 2017 iMac can run the latest intel build of macOS via OCLP. This iMac has either a Radeon Pro 555 or 560, which are made on the Polaris architecture – which is compatible in later versions of macOS. All Core branded products in the 7th generation have AVX 2, so it won’t have issues with hardware acceleration even if the OS is unsupported when using it’s original GPU, as well as any eGPUs.

Details

• Announced June 5th 2017
• Apple model number: A1418 (EMC 3069)
• Model ID: iMac18,2
• Order: MNDY2LL/A (3 GHz i5-7400)
  • MNE02LL/A (3.4 Ghz i5-7500, Radeon Pro 560, 1 TB Fusion)
  • BTO/CTO (3.6 GHz i7-7700)
• Discontinued March 19th 2019

Mac OS

• Requires macOS 10.12.5 (16F2073) Sierra through macOS Ventura 13.7.1 officially.

Core System

This iMac shipped with Quad-Core Kaby Lake 14nm CPUs. Only the i7 has hyper threading. All iMacs use a FCLGA1151 socket, and can be upgraded!

Legend: L1i = L1 Instruction Cache, L1d = L1 Data cache

• Intel Core i5-7400 ($1299): 3.0 Ghz, 4 Cores, 4 Threads, 3.5 GHz Turbo
  65W TDP, 14nm, Per-Core: 32KB L1i/32KB L1d, 256KB L2, Shared: 6 MB L3
  Comes with: MMX, SSE 4.2, AVX 2, AES, EPT, VT-x, VT-d, MPX, SGX
• Intel Core i5-7500 ($1499): 3.4 Ghz, 4 Cores, 4 Threads, 3.8 GHz Turbo
  65W TDP, 14nm, Per-Core: 32KB L1i/32KB L1d, 256KB L2, Shared: 6 MB L3
  Comes with: MMX, SSE 4.2, AVX 2, AES, EPT, VT-x, VT-d, MPX, SGX
• Intel Core i7-7700 ($1599): 3.6 Ghz, 4 Cores, 8 Threads, 4.2 GHz Turbo
  65W TDP, 14nm, Per-Core: 32KB L1i/32KB L1d, 256KB L2, Shared: 8 MB L3
  Comes with: MMX, SSE 4.2, AVX 2, AES, EPT, VT-x, VT-d, MPX, SGX, SIPP, vPro

Memory

• All models: 8/16 GB “2400T” MHz PC4-19200s SDRAM ~19.2 GB/s
  • 8/16/32 GB on 3.4 i5/3.6 i7 model
  • All 3 chips supports up to 64GB, according to Intel.

Video

• Base: AMD Radeon Pro 555, 2 GB GDDR5, Polaris, 768 Cores, 14nm
  • 3 Billion Transistors, 123mm die size, BGA-769, PCIe v3 x8, 81.6 GB/s
  • 850 MHz GPU clock, 1275 MHz Memory clock (5.1 Gb/s effective), 75W TDP
  • OpenGL 4.6, OpenCL 2.1, Vulkan 1.3, 12 Compute units, 16KB L1 Per CU, 1 MB L2
• Option/3.4 i5: AMD Radeon Pro 560 4 GB GDDR5, Polaris, 1024 Cores, 14nm
  • 3 Billion Transistors, 123mm die size, BGA-769, PCIe v3 x8, 81.28 GB/s, DX 12
  • 907 MHz GPU clock, 1270 MHz Memory clock (5.1 Gb/s effective), 75W TDP
  • OpenGL 4.6, OpenCL 2.1, Vulkan 1.3, 12 Compute units, 16KB L1 Per CU, 1 MB L2
• 21.5″ IPS TFT LED-backlit LCD Retina display, 4096 x 2304 @218.5 PPI
  • Support for 1 Billion Colors, 500 Nits Brightness, and P3 Wide Color Gamut
• “Simultaneously supports full native resolution on the built-in display at millions of colors and”
  • 1x 5120×2880/60Hz Billions of colors, 2x 3840 x 2160@60Hz 1 Billion colors, 2x 4096 x 2304 with millions of colors

Drives

• 1 TB 5400 RPM 2.5″ SATA 3.0 (6Gb/s) Rotational Hard Disk Drive
  • Configurable to a 1 TB Fusion Drive (with 24 GB SSD portion)
  • or a 256 GB / 512 GB / 1 TB PCIe-based SSD

Expansion/Misc

• Facetime HD Camera
• 2x USB-C Style Thunderbolt 3 ports with USB 3.1
• 4x USB-A style USB 3.0 ports
• Bluetooth 4.2
• 802.11ac (a/b/g/n) Wifi
• Gigabit Ethernet RJ-45 connector
• SDXC SD-Card slot reader
• 3.5mm Headphone Jack with support for Apple iPhone headset with Mic
• Stereo Speakers
• A single Microphone
• Kensington lock slot
• 185W Power Supply, seems to be shared across models

Included Peripherals

• iMac 21.5″ Non Retina
• Magic Mouse 2
  • Configurable with Magic Trackpad 2
• Magic Keyboard 2
  • Configurable to Magic Keyboard 2 with Numeric Keypad
• Power Cord
• Documentation, Apple Stickers

Physical

• Size:H/W/D 17.7 x 20.8 x 6.9 in/45 x 52.8 x 17.5 cm
• Weight: 12.5 lb./5.66 kg