(Pocket-lint) - A new iMac range is here to woo you into staying with the desktop in 2015 rather than going mobile.

With new processors, new displays, and new graphics options there is plenty to be tempted by. We've been using the new 21.5-inch model with 4K display to find out whether sitting at your desk - now in ultra-high definition - really is still a viable option.

Apple iMac 4K (2015) review: Design

Design-wise the iMac looks the same in 2015 as it did to the last generation of iMacs. If you need a quick refresher, that means a stonking 21.5-inch screen surrounded by a flush glass screen with black bezel, all mounted on an aluminium stand that arcs out the back.

A single power cable spews out from the middle - virtually out of sight - while a bevy of ports, readers and connection options sit to the right hand rear of the device (when facing it from the front).


Everything that you are likely to want is here: four USB sockets, two Thunderbolt sockets, an SD card reader, and Ethernet - and that's before you consider Bluetooth and 802.11ac wireless connectivity.

As we said before, though, all ports are a total fiddle to use without sliding the whole iMac around, as the hinge stand means the screen doesn't rotate horizontally. We'd be just as happy with a larger edge width if it meant some (but not all) ports were side-mounted.

The front, sitting face on, gives away none of the technical marvels happening inside, while from the rear you don't really get any notion either. This is a machine that is as smart as it is minimal and comfortably sits in a kitchen or reception lobby on show for all to see with pride.

iMac 21.5-inch (2015) review: 4K display

While the design might look much the same, what has changed is the display itself. The top-of-the-range 21.5-inch model sports a new 4K Retina display delivering a resolution of 4096 x 2304 pixels. If you don't opt for the top-flight £1199 model then you'll have to settle on Full HD (1920 x 1080) resolution.

That new 4K resolution, which makes the iMac effectively as pixel dense as the company's MacBook and MacBook Pro models across its larger scale, is as sharp as you would hope it to be. Watching 4K footage, editing documents, or surfing the web is an absolute pleasure.


The screen's quality is helped further by a new P3 colour gamut technology Apple has introduced, which, although not exactly the same, takes the same approach many television manufacturers are trying to master for their TVs to deliver deeper, richer colours. Put simply, it boosts red, green, and blue colours and can show 25 per cent more colours than the previous screen tech used by Apple.

That means photos and videos can be punchier, more vibrant, and in Apple's eye's more "true to life". That's going to be especially welcomed if you use DSLRs and pro video cameras capable of capturing a wide colour gamut. While we've enjoyed the new display, the new P3 colour gamut is hard to see unless you are really looking, especially if you haven't got a previous model to compare against. We aren't complaining, but don't buy it for this feature alone.

Still, a crisper screen is a better screen and you will benefit and notice the difference overall. Even dock icons feel punchier, and it is probably best to see it like standard definition compared to high-definition on your TV - once you've spotted it, you'll struggle to go back without a fight.

Apple iMac 4K review: Performance

The 21.5-inch iMac with Retina 4K display sits at the top of the 21.5-inch model family and comes with a 3.1GHz quad-core Intel Core i5 processor (Turbo Boost up to 3.6GHz), Intel Iris Pro Graphics 6200 (no discreet option available, boo), 8GB of RAM, and a 1TB Serial ATA Drive.

Upgrades come in various shapes and sizes. Best decide what you want from the off, as processor and memory upgrades can't happen after the fact. Shame, as the 27-inch 5K iMac offers a port to upgrade RAM after purchase, which we'd liked to have seen here.

There's also the option to go for Apple's Fusion Drive that tries to balance flash and standard storage to enhance performance (worth it for £80 for the 1TB option). The standard storage option, with its 5,400rpm speed, is poor and will be slow compared to anything else you are probably using. The Apple Fusion Drive works by constantly shifting apps you open often or files you access more regularly to a flash storage area, while files or apps you only occasionally use to the slower standard hard drive. It all happens in the background meaning you are oblivious to what's going on.


However, previously Apple gave us a huge 128GB flash drive element within the mix, now that's far smaller at 24GB. Why? Costs and usage. Reducing the size of the drive bring the price down. Obviously this has brought on criticism from many, but your point of view will come down to how much of a power user you are. We suspect that most of those opting for the smaller-screened unit won't notice much of a difference. Whether that Fusion Drive limitation causes an issue with the more beefier 27-inch iMac we will have to see in our separate review.

We noticed slower start-up using only the standard off-the-shelf offering, certainly compared to our flash-drive-powered MacBook Air. It is easy to say, but our recommendation is buy the best spec you can afford, upgrades and all - and there are (pricey) 256GB (£160) and 512GB (£400) flash-only upgrades. We would recommend you upgrade away from the standard 5,400rpm hard drive to drastically speed up boot times and app loading times, and if you can stretch your budget even further get 16GB of RAM for it to really fly.

Still, in use we've found our off-the-shelf iMac 4K with 8GB RAM to be zippy in terms of performance. We've had no trouble streaming, playing back and editing 4K content from a number of sources (including YouTube) that shot with our iPhone 6S.

iMac 21.5-inch (2015) review: Magic Keyboard & Magic Mouse 2

Aside from the main all-in-one computer, Apple has also updated the Magic Keyboard, the Magic Mouse, and as an alternative, the Magic Trackpad.


The keyboard and Force-Touch-enabled trackpad (latter not included) ditches the AA battery compartment at the rear to create devices that come with a much slimmer, flatter profile, as well as introducing rechargeable power (it lasts about a month) and instant pairing via a Lightning cable. Pairing is ingeniously quick.

READ: Apple Magic Trackpad 2 review: Feel the Force Touch

Everything is now quieter too. The Magic Keyboard comes with bigger Function keys, a slight rejig of the arrow keys, but stays fairly true to the cause. The keys feel physically softer to depress and the individual key mechanism doesn't feel as spongy or noisy as previous offerings from the company - which is a good thing in our books. It is not the same mechanism as found on the new MacBook, though, if you are wondering.

The Magic Mouse 2 also ditches the AA batteries, takes a couple of minutes to charge (you can't use it while you charge it but considering the fast charge times this isn't really an issue), and sports a very thin profile that we actually found pretty uncomfortable to use (in fairness we gave up using a mouse for a trackpad around five years ago). Accountants, there's no number pad option.

iMac 21.5-inch (2015): El Capitan

The new iMac runs Apple's latest OS X: El Capitan straight out of the box. This means a number of new-and-improved features over previous outings, including last-generation Yosemite.

READ: Apple OS X El Capitan review: Tweaks rather than overhaul for free update

Split View certainly benefits from the big screen real-estate on offer from the new iMac, allowing you to happily work on two apps side by side, while performance enhancements make everything run that little bit smoother.

It's largely small tweaks, though, but it's the best iteration of OS X to date.


If you are still wanting to be bound to the desk and go Apple then the iMac is certainly the way to do it. Going Retina is certainly worth the extra cash with this 21.5-inch model - delivering ultra high-definition 4K without breaking the bank.

The clean and minimalist experience is a joy, and performance is good - so long as you upgrade those vital components. The lack of post-purchase RAM upgrades is a shame (they're now soldered in), while the latest Fusion Drive's drop in flash storage (24GB down from 128GB) is disappointing, but unlikely to affect most users.

Sadly, we suspect most won't realise the real benefit of the new P3 colour gamut screen - which is a great bit of technology that won't really be properly appreciated - unless photography or video editing is your main chosen field. If that's the case then, well, the beefier 27-inch iMac is probably the way to go anyway.

The new iMac 21.5-inch is simple, elegant and a great way to get 4K resolution on the desk.

Writing by Stuart Miles.