Apple 21.5-inch iMac review (late 2015) - still the all-in-one standard
Processor: Dual-core 1.6GHz Intel Core i5-5250U, RAM: 8GB, Front USB ports : None, Rear USB ports: 4x USB3, Total storage: 1TB hard disk, Graphics card: Intel HD Graphics 6000, Display: 21.5in built-in glossy, Operating system: Apple OS X El Capitan
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.