Reckon you’re pretty good at Spot the Difference? Try all you like - you’ll need full-on X-ray vision to see what’s changed between last year’s 21.5in 4K iMac and this all-new model.

That’s because underneath the familiar, ultra-minimal silver shell, Apple has given its dinky desktop a major makeover. We’re not talking a few tweaks and changes, but a complete overhaul with faster CPUs, speedier storage, and dedicated graphics to push all those pixels.

Oh, and lets not forget a brighter display that uses the same wide colour gamut as the digital 4K projectors in your local multiplex. Only this time it’s even more brighter and more colourful.

It’s the screen that really makes this new iMac stand out - as if you’re going to spend all day staring at one, you’re going to want it to be the best.

Look no further, then - this is as good as it gets in an all-in-one.


That all-new panel has been squeezed into the same aluminium unibody chassis Apple has been using for a few years now - which is no bad thing. I still reckon it’s the best-looking all-in-one computer around, with the exemplary build quality you’d expect - even if you still can’t adjust the screen beyond a simple tilt.

It’s an exercise in minimalism, with curves in all the right places and no visible lines or seams. It feels like it belongs in a Zen garden, not on a desk.

You’ll have to head to the back of the iMac to spot where things have changed. Apple has added two Thunderbolt 3 ports to the existing array of four USBs, for super-quick file transfers and hooking up external displays. They conveniently double up as USB-C ports, too.

The usual SD card reader, 3.5mm headphone port and Ethernet port all make a reappearance too. They’re still awkward as hell to plug things in to without swivelling the whole machine around so you can see what you’re doing, but this 21.5in model weighs so little that it’s hardly a chore.


It’s underneath that gorgeous glass front that you’ll find all the real action, including one of Intel’s 7th generation Kaby Lake CPUs. The one in this entry-level 4K iMac usually ticks along at 3GHz, but can clock all the way up to 3.5GHz whenever you need more go-juice.

Combined with 8GB of RAM, there’s enough power here for just about any desktop task - and that includes editing huge high-res images, or even cutting together multiple 4K video streams. I didn’t experience a jot of lag or stutter when scrolling around the macOS desktop, and could run a handful of apps happily without things slowing down.

If you’ve got last year’s iMac the difference won’t be huge, but basically, unless you’re creating 3D models or doing seriously taxing CAD work, even this baby iMac will have the grunt to cope.

Graphics have been given a shot in the arm, too, with this basic 4K model getting a dedicated AMD GPU for pushing all those pixels. The Radeon Pro 555 has 2GB of dedicated video memory, and is at least twice as fast as last year’s model - in both professional 3D rendering and games.

4K gaming is still asking a lot, of course: try to pop a cap in a terrorist in Counter Strike: Global Offensive and you’ll need to drop down to 1080p to get properly smooth frame rates. Older titles and less-intensive games like Blizzard card Battler Hearthstone are perfect for some full-screen, native resolution action though.

It’s a shame you don’t get an SSD as standard, but a 1TB is the next best thing: it’s got a small amount of flash memory with really nippy read and write speeds, plus a huge hard disk for storing all the files you don’t need at a moment’s notice. You’ll have to spend extra to get an SSD, but if you do splash that cash, you’ll get one that’s about twice as fast as last year’s model.

Tech Specs 
21.5in, 4096x2394 resolution LCD w/ DCI-P3 wide colour gamut
3GHz 7th-generation Intel Core i5 (Kaby Lake)
AMD Radeon Pro 555 w/ 2GB VRAM
1TB hard disk
4x USB3, 2x USB-C/Thunderbolt 3, Ethernet, 3.5mm headphone, SDXC card reader, 802.11ac Wi-Fi, Bluetooth 4.2
Apple MacOS 10.2 Sierra
Magic Keyboard, Magic Mouse 2, Lightning cable
450x528x175mm, 5.66kg
Stuff says... 

Apple 21.5in iMac with Retina 4K display (2017) review

Updates to almost every area hammer home the 4K iMac as the best all-in-one system around
Good Stuff 
Fantastic display combines resolution and colour refinement
Dedicated graphics a welcome step up from last year
Baby Lake CPUs bring the power
Bad Stuff 
No Target Display mode to use that stunning screen with other kit
Screen only has tilt, I guess?