27-inch iMac 2017 review: more than a 5K display

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27-inch iMac 2017 review: more than a 5K display

Apple's latest 27in all-in-one with 5K screen might look the same as last year's model, but inside is another story.

Any other manufacturer would have been accused of flogging a dead horse by now. Another year has rolled by without a significant change to the design of the iMac and, by the looks of things, Apple fans will have to wait at least another year until that happens.

Is that a serious problem? No. If there’s one thing you need to know about the new iMac, it remains the best-looking all-in-one computer ever made.

And while the design may have remained the same for three years, the specifications certainly haven’t. This is the second generation iMac with a 5K (5120 x 2880-pixel resolution) screen – and there are still very few 5K monitors that you can go out and buy. 


The Retina display on the original 5K model was already superb, yet the despite the lack of competition in this type of display, Apple has gone and improved the display yet again. It’s boosted maximum brightness by a claimed 43% to build on what was already a stunning screen. Like the previous model, the new 5K iMac is capable of producing not just the sRGB colour space with incredible accuracy, but also the wider DCI-P3 colour gamut.

Forget about the geeky intricacies for a moment, though, and you can summarise the iMac’s display like this: it’s bright, insanely crisp and whether you’re dabbling in Photoshop, Final Cut Pro or just shooting everything in sight in BioShock Infinite, it looks stupendous. Black is really very black; white is very, very white. We simply haven’t seen many better displays than you’ll find here, and for most people, it’s the pinnacle of display performance.

Let’s introduce some numbers to back this up. Our X-Rite i1Display Pro colorimeter is a harsh mistress, capable of revealing the shortcomings that all but the best-trained eyes would struggle to see, but the Retina display puts up quite the fight. Brightness rises from a slightly silly 466cd/m² to an even more outlandish 527cd/m² (those are the kind of figures I’d expect from a top-notch TV, not a desktop monitor) and contrast hits a ratio of 960:1, which is very good indeed.

Colour accuracy is fabulous, as we’ve come to expect from Apple. The last model we reviewed hit an average Delta E of 0.7 and this year’s is only slightly worse at 0.97. The panel whips up 98.9% of the DCI-P3 gamut, bar the most intense shades of magenta and blue. This is very good news if you understand what it means – and, trust me, it really is, even if you don’t have a clue what I’m on about.

Oh, and by the way, if you fancy plugging in your MacBook and using the iMac as a 5K monitor, well, tough – you can't. Apple still doesn't support Target Display mode on the 27-inch iMac, despite adding Thunderbolt 3 support via a pair of USB Type-C ports on the rear of the machine.


If you were inquisitive enough to rip open the iMac then you’d find a completely revamped set of innards. Inside, seventh-generation (Kaby Lake) quad-core Intel processors have been introduced next to a selection of new AMD Radeon Pro graphics chips and the combination delivers a decent boost to performance.

It’s not night-and-day stuff, but the changes are definitely welcome. The quad-core 3.4GHz Intel Core i5-7500 in our review model is the slowest chip available in the range, with other choices including the 3.5GHz Core i5-7600, the 3.8GHz Core i5-7600K and the 4.2GHz Core i7-7700K. Memory is available in 8GB, 16GB, 32GB and 64GB configurations; our test iMac came with 8GB.

In our in-house benchmarks the 3.4GHz model turned out to be quicker than the sixth-generation 3.2GHz Core i5 model we tested back in 2015 by a margin of 9% (overall score 109), which is similar to the improvement that model delivered over the 2014 model (a 10% boost, with an overall score of 100 versus 91). In all honesty, it isn't a huge performance boost; certainly not big enough to notice in everyday use.

As for graphics performance, that’s a bit more impressive. This year, depending on the model, you’ll get either an AMD Radeon Pro 570 (with 4GB of VRAM), an AMD Radeon Pro 575 (with 4GB of RAM) or an AMD Radeon Pro 580 (with 8GB of VRAM), and the difference over 2015’s 27in 5k iMac is significant.

We’ve only had the chance to test the AMD Radeon Pro 570-equipped model, which is in the lowest-spec 5K iMac this year, but with results that beat the last edition’s top-end model – and by quite a distance – it’s a major step forwards. Whether you’ll be able to game smoothly at the screen’s native 5K resolution is another matter entirely, however.

We put the iMac through its paces using Unigine’s Heaven Benchmark – a pretty good representation of how much gaming grunt a machine has – and it reveals that, although much faster than before, the iMac’s GPU power is still comparatively limited.

At 2,560 x 1,440-pixel resolution and Medium detail, the Pro 570 in our review unit achieved a mostly smooth 42fps, which is double that of the 2015 iMac’s 26fps (R9 M390) we tested last time. If that sounds good, though, remember this test still isn't running at the full 5,120 x 2,880-pixel the display is capable of; the benchmark simply doesn’t run at such high resolutions and even if it did, you could expect the frame rate to drop significantly.

The 5K iMac we’ve reviewed here has a 1TB Fusion Drive, with the top-end model available with a 2TB or 3TB disk. Sadly, it’s not nuclear-powered, – this would be simultaneously both worrying and very impressive – but it does combine a superfast SSD with an old-school hard disk.

The theory is that all your regularly used applications and data end up on the really-very-fast SSD, and everything else gets plonked onto the HDD. There isn’t much change to the amount of SSD storage on offer here, though, with this year’s 1TB drive boasting 32GB of fast flash storage compared to the 2015 model’s 24GB.

If you want to get back up to the 128GB flash storage that was offered on the original iMac 5k's Fusion Drive, you’ll have to move up to the 2TB or 3TB model.

Does the Fusion Drive work, though? It is very quick in benchmarks, but it’s difficult to say how well the system will work once you’ve filled the storage with the accumulated gunk of several years' use. Out of the box, it’s pretty fast – we clocked it at around 987MB/sec while reading files, and 130MB/sec while writing them back to the disk. That’s faster for reads than the previous model, although a touch slower for writes.

This is nowhere near as lightning-fast as the pure flash storage in the latest MacBook Pro laptops, however. If that sort of performance is paramount, then you can swap to SSD-only storage with 256GB, 512GB, 1TB and 2TB SSD options available for various models.

Next: input devices, connectivity, design and verdict

Apple Magic Keyboard, Magic Mouse 2 and Magic Trackpad 2

Magic, eh? What Apple is on about we have no idea. Keyboard, mice and touchpads are about the least magical parts of our daily existence. However, Apple’s accessories are pretty special.

The Magic Trackpad 2 is the same as it was last time out, but that's no bad thing. It has the air of a Philippe Starck-designed door wedge and is more expensive than ever at $179. If you’d rather have your magic in Touchpad rather than mouse form, you can swap it for $70 when you buy it with your iMac. Want both a mouse and a trackpad? Then that’ll be a further $179.

It’s still a wonderful thing, though, with a 30% larger touch surface than its predecessor and Force Touch providing that extra layer of luxury. Powered-off, it’s a large slab of cold, unclicky frosted glass, but flick the switch and it provides all the handy Force Touch functionality and gesture-controlled loveliness we’ve come to expect from my MacBook Pro.

Touchpads on a desktop might sound like a rubbish idea, but Apple really makes it work – flicking between multiple desktops and whizzing up Mission Control is super, super fast and instinctive. Plug it in, use it, and – trust us – you’ll miss it when it’s gone. The coolest feature? Oh, Silent Clicking. Enable this in the control panel and the high-pitched click disappears, leaving only the low-frequency thump to be felt through your fingertip. For those who value silence above all else, it’s a great party trick.

It’s harder to get excited about the Magic Keyboard 2. It’s quite flat, which is due entirely to the removal of the AA battery compartment from the old Magic Keyboard, so depending on how you like your keyboard to be angled, this may not be your bag at all. However, there is at long last an extended version of the keyboard with a numeric pad stuck on the side. Yours for another $40.

Whichever model you choose, though, it's as nice to type on as the previous model. The function keys along the top are now all full-sized, and the left and right cursor keys have grown slightly.

What about the Magic Mouse 2. It’s a mouse. It’s wireless. It moves cursors all day, every day. It’s comfy to use, and although there still aren’t discrete left and right buttons, it works so predictably that there may as well be.

The AA batteries of the original have been flung out in favour of a lithium-ion battery that charges via – yup, you guessed it – a Lightning cable. It’s bundled with the iMac for free. It really isn’t desperately exciting. And if, like me, you really do like games, it’s not the greatest choice. A cheaper USB gaming mouse would make a much better bet. However, it is very, very nice to look at.


One thing annoying about the iMac is the positioning of the ports – they’re all hidden around the right-hand rear of the iMac, so plugging in a USB device involves far too much getting up and leaning around the screen. If you do a lot of that, you might want to get yourself a USB hub.

Still, once you have got up and peered awkwardly around the back of the iMac, there’s all the stuff you’d hope for and more. Four USB 3, one Gigabit Ethernet, an SD card reader and a headphone output that, alas, no longer doubles as an optical digital audio out. A small but annoying step backwards.

There are a couple of new ports here, too, with a pair of Thunderbolt 3 USB Type-C ports supplanting the Thunderbolt 2 ports of old, doubling potential data transfers from 20Gbits/sec to 40Gbits/sec and opening the way for external graphics acceleration once MacOS High Sierra arrives later in the year.

Factor in 802.11ac and Bluetooth 4 wireless networking stuff and the iMac hits all the right notes. You can even whip off a panel at the rear and add more RAM. There are four slots, with two occupied as standard and you should be able to add up to 64GB.


The physical design, as we mentioned at the start, hasn’t changed a jot since 2014, and that’s because it’s already ridiculously good looking.

In fact, we only have a couple of gripes with the iMac. The first is that there’s no height adjustability – you can only tilt the iMac back and forth. And, let’s be honest, sticking a pile of books under your brand-new iMac is hardly the done thing. The second is the 27mm-wide bezels surrounding the screen. In 2017 these are starting to look a little, well, fat.

Other than this, the 2017 27in 5K iMac is every bit the classic introduced back in 2014 and with the iMac Pro due to arrive later in the year, Apple shows no signs of killing it off or subjecting it to significant overhaul just yet.

Pricing and conclusion

So let’s keep this brief: the Apple 27-inch iMac with Retina 5K display is still fantastic. But which one should you get? That depends on your budget.

The $2,699 base model offers 3.4GHz Intel Core i5-7500 processor, 8GB of RAM, 1TB Fusion Drive and Radeon Pro 570 graphics. The next model up, at $2,999, adds a 3.5GHz Core i5-7600 chip and Radeon Pro 575 graphics, while the $3,449 model includes a 3.8GHz Core i5-7600K, 2TB Fusion Drive and Radeon Pro 580 graphics. Adding a 4.2GHz Core i7-7700K costs an extra $320 in the high-end model, while a 3TB Fusion Drive adds $160.

Memory and storage are configurable, but they aren’t cheap. Adding RAM costs anything from $320 (for 16GB) to $2,240 (64GB), while swapping out a Fusion Drive for an SSD ranges from $160 (256GB) to $2,240 (2TB).

The truth is even the affordable base-model iMac is perfectly fine for most uses, now that it’s no longer hobbled by a non-Fusion Drive HDD. And while you could never call $2,699 cheap, it is very good value for money. A display of this quality would set you back well over a grand on its own, it wouldn’t look anywhere near as pretty, and it wouldn’t come with a fast, capable, fully functioning computer built in.

If you’re worried about future proofing, that’s less of concern with Mac OS High Sierra set to offer support for external graphics acceleration. With a breakout box and the right graphics card, you should be able to upgrade your graphics performance, giving you more time to save up for your next iMac.

Sure, you could build a faster desktop PC and make do with a 4K monitor, but as with most Macs, the sum is greater than the new parts – and those parts of the new iMac are very good.

This review is based on an article that originally appeared at alphr.com.

Seventh-generation Intel processors, faster Fusion Drives and better graphics have given it a much-needed boost. The (2017) 27-inch iMac with Retina 5K display can get pricey if you want the best specs, but the entry-level model is very good value.
From $2699 AUD
27-inch 5120 x 2880-pixel (5K) Retina display; 3.4GHz Intel Core i5-7500, 3.5GHz Core i5-7600, 3.8GHz Core i5-7600K or 4.2GHz Core i7-7700K processor; 8GB, 16GB, 32GB or 64GB of RAM; AMD Radeon Pro 570, Radeon Pro 575 or Radeon Pro 580 graphics; 1TB, 2TB of 3TB Fusion Drive or 256GB, 512GB, 1TB or 2TB SSD; 4 x USB 3 ports, 2 x Thunderbolt 3 (USB-C) ports, SDXC card slot; 802.11ac Wi-Fi, Bluetooth 4.2 and Gigabit Ethernet.
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Copyright © Alphr, Dennis Publishing

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