Apple iMac 21-inch review (late-2015): A little computer with a LOT of pixels

So, the 27-inch iMac is too big, you don’t want a MacBook and the Mac mini doesn’t quite hit the spot. The 21.5-inch iMac could be just what you’ve been looking for. Following in the much larger footsteps of its king-sized cousin, the baby iMac of the family has upped its game with updated processors and an optional Retina 4K display.

Apple 21.5-inch iMac (2015) review: What’s new?

I know it’s bad form to start a review on a downer but, well, here we are. In an act of unspeakable cruelty, Apple initially neglected to send us the model with the Retina 4K display (Apple has since rectified this cruel omission, so I’ve added my thoughts on the 4K display on the next page). My hopes, dashed. Instead, I excitedly ripped open the packaging to reveal the entry-level £899 model ($995 on Amazon US) – the cheapest iMac of the lot. Disappointed isn’t the word.

There’s no 4K display, no Fusion Drive – not even a Magic Trackpad 2 to soften the blow (that’s £44 extra, thanks). Instead, all you get is an iMac with a 21.5in Full HD display, a 1.6GHz Core i5 processor, 8GB of non-upgradeable RAM and a bog-standard 1TB hard disk. Oh, and a Magic Keyboard and a Magic Mouse. For £899 (though the next model up is now pretty near in price at £964 on Amazon UK). If that doesn’t sound like anything remarkable, it’s because it isn’t – this is intended as a basic, everyday computer. Albeit a rather expensive one.

Want something a bit quicker? That’ll cost you. Bump your budget up to £1,049, and you get a much beefier-sounding 2.8GHz processor, while £1,199 will buy you an even faster 3.1GHz Core i5 processor and a Retina 4K display.

Whichever of these you choose, however, the iMac has a positively prehistoric 1TB 5,400rpm HDD. This, if you’re wondering, is the technical term for “very, very slow hard disk”. In fact, this is the first brand-new iMac I’ve used in many years that has felt sluggish straight out of the box. Yes, I’m probably spoilt by the flash storage in my MacBook Pro, but spending an extra £80 on the 1TB Fusion Drive upgrade is an absolutely essential addition. You’ll regret it if you don’t.

And if ludicrous speed is absolutely of the essence, then thankfully there are other options. Alternatively, you can spend another £160 on 256GB of super-fast SSD storage and, if that’s just not good enough, the other upgrades – moving up to a 2TB Fusion Drive or a 512GB SSD – are only available on the range-topping £1,199 Retina 4K model.

Oh, and one other thing: since the 21.5in iMac’s RAM is soldered onto the motherboard, you can’t upgrade it in the future. If there’s the slightest chance that you might need 16GB of the stuff, then decide now or forever hold your, erm, memory capacity. (That’ll be another £160, by the way.)

Apple 21.5-inch iMac (2015) review: Design

Visually, though, the iMac hasn’t changed a jot. It’s still a drop-dead gorgeous, and pleasingly compact, all-in-one PC, and even if the screen’s bezels are beginning to look a bit on the chunky side, the design alchemy of metal, glass and perfectly-tailored curves still looks great from any angle. There aren’t many PCs I’d want to see the back of, but the iMac is one of them. It’s so pretty, in fact, that it almost seems a shame to plug in any cables at all.

On that note, you may be seeing more of the iMac’s rear than you want to. All the ports – the four USB 3, two Thunderbolt 2, Gigabit Ethernet, SD card and headphone jack – are located at the back. And unless you want to run the risk of gouging the iMac’s perfect metallic hide by blindly trying to insert a USB flash drive, you’ll have to get up and twist the iMac around every time you want to plug something in. It may be annoying enough to make you rush out and buy a USB 3 hub. 

Still, the arrival of super-fast Thunderbolt 2 ports goes a little way towards making amends, and the wireless side of things is well-covered: 802.11ac Wi-Fi and Bluetooth 4.1 are enough to cheer anyone up.

What’s more, the 21.5in iMac now comes with Apple’s upgraded set of Magic accessories. The Magic Keyboard 2 and Magic Mouse 2 are supplied as standard, and you can swap the mouse for a Magic Trackpad 2 for £44, or have both for £109. If you want to find out more about what I think of Apple’s magical new accessories, then you can read what I wrote in my 27-inch iMac with Retina 5K display review. In short, they’re very nice. I like them, mostly, and you probably will too.

Apple 21.5-inch iMac (2015) review: Full HD display

If you’re considering buying one of the cheaper 21.5in iMacs, I have one essential piece of advice: do not under any circumstances look at any Retina iMacs or MacBooks before spending your cash. If they’re nearby, close your eyes and walk straight past. This is very, very important. If you so much as peek at a Retina display, the standard 21.5in iMac will look utterly, utterly mediocre by comparison; all crude, obvious pixels and jagged, stair-stepped text. Trust me, you get used to the sharpness of Retina displays near-instantaneously, and when you go back to a normal display – well, it looks pretty rubbish.

Still, by the standards of Full HD displays, the iMac’s 21.5in screen is really very good. The bright, high-contrast IPS panel does a terrific job with everything from movies and photographs; the panel produces all the colours most people would ever want it to; and it’s accurate, too, so whatever’s onscreen looks exactly how it should. And in all fairness, if you’re used to using a larger 23in or 24in Full HD monitor, the 21.5in iMac will actually look a little sharper, as the pixels are crammed into a smaller space. Just don’t look at the Retina 4K iMac – or you will have to buy that instead.

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

Trust me on this, the Retina 4K screen really is something special. The iMac’s 4,096 x 2,304 resolution serves up 14% more pixels than most 4K monitors, and this means only one thing: images are outrageously sharp. Crystal clear is an understatement.

I’d even go as far as to say it was a better all-round display than that of the 27-inch Retina 5K display. Why? Simple. It’s only an imperceptible sliver less colour accurate according to our X-Rite colorimeter (the average DeltaE is 1.1, if that means anything to you), but it’s every bit as bright (446cd/m2), reproduces the same range of colour (86.5% of the Adobe RGB gamut), and the contrast ratio of 1,247:1 is astonishingly good. 

So, why is it better? Because the backlighting is far, far more even than its larger 5K sibling, which means that colours are far more even and uniform across the panel. Where the 27-inch iMac suffers due to a backlight which varies in intensity by as much as 15% as you look across the display, the 21.5-inch iMac is much more even-handed, varying by no more than 7%. For designers and visual artists who need to know that what’s onscreen is faithful, this is an important distinction.  

Apple 21.5-inch iMac (2015) review: Performance

Apple has also been tinkering with the iMac’s insides. Curiously, Apple hasn’t transplanted the latest Intel Skylake processors, instead equipping the iMac with last year’s Broadwell chips. The spoilsports. Also, the discrete Nvidia graphics chips of last year have disappeared – the iMac now makes do with the integrated graphics chip on the Intel CPUs. That means you can wave goodbye to half-decent gaming performance, for starters.

The entry-level model comes with a 1.6GHz Core i5-5250U processor. This is not at all exciting. If that CPU sounds at all familiar, it’s because it’s more commonly found in laptops – it isn’t the slightest bit fancy, nor is it particularly fast. It’s fine for basic tasks – an overall score of 42 in Alphr’s Incredibly Demanding Benchmark Suite proves as much – but if you need something that’ll fire through more heavyweight photo or video editing, then an upgrade to the 2.8GHz model will be very worthwhile. And as I mentioned earlier, the subjective experience isn’t helped at all by the 1TB HDD. Push the iMac with multitasking or tougher applications, and it gets bogged down quickly.

Gaming is not the 21.5in iMac’s forte, either. I fired up the Unigine Heaven benchmark, and at Full HD and Medium detail, the iMac managed a juddery average of 12.8fps. It’s worth noting that the faster Intel CPUs on pricier models do have better GPUs – and hence more gaming power – but they’re still not going to handle the latest titles. If you want to stand any chance of squeezing playable frame rates from the 21.5in iMac, you’ll need to drop the resolution and detail settings right down.

Apple 21.5-inch iMac (2015) review: Verdict

Depending on your point of view, and which model you’re looking at, the 21.5in iMac is either a stroke of minimalist genius or an overpriced poseur. Apple’s decision to employ slow HDDs across the range is cynical at best and, given the complete lack of upgradability, may end up hobbling many customers in years to come. Ooh, it makes me mad.

In all honesty, the entry-level £899 model probably isn’t worth considering at all. It’s underpowered, underwhelming and just doesn’t deliver the slick, assured performance that I’d expect from a machine at the price. A Fusion Drive will help, but the slow CPU means it’s likely to find itself out of its depth in just a couple of years.

Personally, I’d ignore all but the top-end Retina 4K model. The Fusion Drive upgrade bumps the price of that pixel-packed model to £1,279, but, with that done, you’re looking at a very capable all-in-one PC that unites a high-DPI display and decent performance in a compact, unfussy package. The fact that it looks rather dashing certainly doesn’t hurt. 

As ever, the eternally power-hungry or upgrade-happy should look elsewhere (full disclosure: yes, you can buy dramatically faster, easily upgradeable desktop PCs for the same, or less, money), but if you want the best, compact all-in-one PC on the market – the 21.5in iMac is still, for all its flaws, the one to beat.

Read more: If 21.5in is roughly five and a half inches too few, then click here to check out Alphr’s review of the Apple 27-inch iMac with Retina 5K display. It’s bigger, better and rather beautiful, too.