Apple 21.5-inch iMac review (late 2015) - still the all-in-one standard

The entry-level iMac often gets forgotten in the world of Retina, 5K and desk-filling displays, but the 21.5in iMac still looks the part and is one of the cheapest ways to buy a desktop computer running OS X, save for the diminutive Mac Mini. It's also easily the best-looking all-in-one available, so if you're platform agnostic but want something pretty to grace your home, then this is it.

Design, build and screen

For £899 you get a fabulous-looking, wafer thin aluminium chassis, complete with sharp corners, tapering backside and robust stand. The current design is practically unchanged from when it first appeared in 2012, which itself is a mere evolution of the original unibody iMac look, but it still makes an impact - especially on those still using pre-2012 iMacs. I had several envious looks from colleagues who haven't been given an upgrade.

The placement of ports remains frustratingly unchanged, however. Admittedly this is so the iMac can maintain its uninterrupted lines and svelte figure, but it ameans you'll have to disturb your entire desk by rotating the iMac 45-degrees to reach any of the four USB ports, two Thunderbolt 2 connectors, 3.5mm audio jack or SD card reader. Apple doesn't supply any extension cables for USB devices and the supplied wireless Magic Keyboard does not come with any connectors. 

^These are still awkward to get to - bring on reversible USB-C

Away from this small irritation, there are other things about the iMac that don't compare favourably to Windows-powered PCs. One is fundamental: the screen size. Looking around the office, 24in monitors are the now the norm, and that's true at home too. 21.5in feels very small. Apple has fitted a Full HD panel with a glossy coating, which means colours jump out with a surprising degree of vibrancy. The glossy coating means you'll occasionally see yourself reflected in darker images, but the glass does a good job of muting reflections from most sources.

Actual screen performance is very impressive, with wide sRGB gamut coverage and decent contrast. We measured these at 97.7% and 919:1 respectively. However, contrast varies depending on your screen brightness settings: with automatic brightness enabled, the backlight adjusts to suit the on-screen image. This can be distracting, especially if you're working on a colour-sensitive project. Luckily it's easy to turn off in the OS X System Preferences menu. Adobe RGB coverage is much lower at 68.8%, so if you're working in print, you'll need to buy a higher-spec iMac, such as the 4K 21.5in model or the 5K 27in, which have greater colour accuracy.

Apple continues to produce the best built-in speakers around, and while things haven't changed for this year's model, they didn't really need to. Impressive bass, clear mid-range and controlled treble means you won't need to augment your iMac with desktop speakers, unless you work with audio, of course.

Performance and upgrades

Buy a budget iMac, get budget performance. The dual-core Intel Core i5-5250U is a notebook-spec chip that you'd expect to find in a mid-range laptop. There's no real problem with this; I've always found U-spec Intel Core i5 processors to be most agreeable in Windows laptops, and the silky Mac OS X El Capitan continues to feel as buttery smooth as ever. There are occasional hiccups when opening multiple programs at once, though, and multimedia tasks, while handled capably, won't be anywhere near as fast as they would be on the more expensive models. It managed an overall score of 42 in our 4K benchmarks, which is very respectable for a dual-core processor. If you're a multimedia professional, you'll know that the occasional hangs you get in Photoshop and Illustrator can be annoying, so if you have the budget to spend a little more on the quad-core 2.8GHz Core i5 model (from £1,049), you absolutely should. If you're just looking for a capable all-in-one for more modest tasks and occasional multimedia use, then this base model will suit you just fine. The base model comes with 8GB of RAM, which is enough for most modest multimedia projects. More complex, high-resolution video projects will require more, and Apple lets you double your RAM for a cool £160.

The integrated Intel HD Graphics 6000 won't be able to cope with the latest 3D games at high resolutions, but I had no problems firing up a quick game of Hearthstone, which ran smoothly and without incident. Older 3D titles will be playable, but you'll want a higher-spec 27in iMac if you want to play a few games.

The base specification only includes a mechanical hard disk. The 1TB capacity is reasonable, but it's disappointingly slow, managing around 100MB/s read and write speeds in the BlackMagic disk benchmark. If you already own a MacBook with an SSD, you'll definitely notice the speed difference when transferring files, and with no way to upgrade post-purchase you'll want to pay extra for faster storage. The £80 1TB Fusion Drive includes 24GB of SSD cache, which OS X intelligently moves your most frequently accessed files and programs to for improved performance. Alternatively, 256GB of fast flash storage will set you back £160.

Peripherals

The 2015 iMac includes the Magic Keyboard 2 and Magic Mouse as standard. The new keyboard is wedge-shaped, with a slightly clickier and more responsive keypress action. The F-buttons, which also have multimedia controls, are larger than the previous model, which is especially handy when reaching for the play/pause and mute buttons. It's perfectly decent for office use and general typing, but the compact size and lack of a number pad may limit its appeal among those that do a lot of number crunching. It now uses a rechargeable battery, rather than AAs like the old model, and you should get around a month of use between charges.

I've never been particularly fond of Apple's Magic Mouse; it always feels a bit stodgy when compared to the firm's excellent touchpads, but the multitouch-sensitive touch surface is much more useful than a scroll wheel - particularly in OS X, which is designed with four-way swipe gestures in mind. It too gets a rechargeable battery instead of AAs. The Lightning port is on the bottom of the mouse, so you can't use it while it's charging, but you should get around a month between charges and you should get around nine hours' of use from a little over two minutes of being plugged in, so this shouldn't be a major problem.

^The Magic Trackpad 2 and Magic Keyboard 2 line up satisfyingly well

Apple also sent a Magic Trackpad 2 with our review unit. Fans of the old Magic Trackpad might be slightly dismayed at the white coating, which looks like a dirt-attracting nightmare, but they'll probably be won over by the impressive Force Touch integration. There's no physical click action any more; attempting to do so when the Trackpad is switched off and nothing will happen. The clicking action is controlled by software, sensing the pressure of your touch and creating an artificial clicking action that's indistinguishable from a real click. Press a little harder and you'll get a Force Click, which activates secondary functions, like a conventional right or middle click.

The number of built-in Force Click functions in OS X was limited at the time of writing, although still useful. Force Click on a hyperlink in Safari and you'll get a preview of the linked page in a small box. Force Click on a word in a document or on a web page and you'll be given dictionary definitions. There are also functions built-in to third-party software, but its integration is still limited. If you want the Magic Trackpad 2 instead of the Magic Mouse 2, you'll pay an extra £44.

Conclusion

The 1TB hard disk is more than a little disappointing, as is the fairly significant cost of upgrading to a Fusion Drive and a Magic Trackpad 2, and don't get me started on the placement of those ports, but the cheapest 21.5in iMac is a capable and well-built machine. It doesn't offer the outright performance of its more expensive siblings, but it's a fantastic way to get yourself an all-in-one with decent software and performance. Alternatively, check out the Mac Mini if you're happy to provide your own display.