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Apple iMac (27-inch, 2017) review: Apple doesn't mess with success

New components under the hood make for a faster iMac. But they’re packed into the familiar chassis of yesteryear.

Lori Grunin Senior Editor / Advice
I've been reviewing hardware and software, devising testing methodology and handed out buying advice for what seems like forever; I'm currently absorbed by computers and gaming hardware, but previously spent many years concentrating on cameras. I've also volunteered with a cat rescue for over 15 years doing adoptions, designing marketing materials, managing volunteers and, of course, photographing cats.
Expertise Photography, PCs and laptops, gaming and gaming accessories
Lori Grunin
6 min read

Apple dusts off its veteran 27-inch iMac all-in-one, updating it just enough to bring it up to 2017 standards for speed and features, as well as to brighten its 5K display and give it the ability to simulate more colors. In practice, that means Apple incorporated 2017 versions of Intel processors and AMD graphics, added support for Bluetooth 4.2, and replaced the old Mini DisplayPort connectors with two Thunderbolt 3-capable USB-C ports.


Apple iMac (27-inch, 2017)

The Good

The Apple iMac's 27-inch 5K display remains the most color-accurate monitor we've seen thus far in an all-in-one, and performance is much improved. Plus it's got two USB-C/Thunderbolt connectors which can drive more external displays and faster file data transfers.

The Bad

The overall design remains unchanged since 2014 -- including the inconvenient rear-mounted ports and SD slot.

The Bottom Line

The already impressive 27-inch 5K iMac gets some welcome spec upgrades for 2017, but rival Windows machines have closed the gap.

These modest updates were announced at  Apple's 2017 WWDC conference, alongside similar spec bumps to the 21.5-inch iMac, the MacBook and MacBook Pro lines, and even a very small CPU bump for the MacBook Air. In fact, except for the Mac Mini, nearly the entire Apple computer lineup has been refreshed for 2017.

This model does deliver a significant speed boost over older models, with performance comparable to current Windows competitors. Plus, at least for this fleeting moment, it's the only all-in-one to offer Radeon RX 580-class graphics (in the guise of Apple's custom but seemingly identical Radeon Pro 580 version).

The Retina 5K display also remains best-in-class, as well as easier to configure than most Windows 10 systems with their needlessly confusing integrated/discrete graphics architecture. The fast data transfer rate of the Thunderbolt 3 ports helps for future-proofing, but at the moment there aren't many drives that can take advantage of the spec's 40Gbps bandwidth. There are a few fast, expensive SSD RAID configurations -- the fastest I could find topped out at 22Gbps (2,800MB per second) -- but most current drives are designed for USB 3.1's 10Gbps maximum.

However, if you have the 2014 or especially the 2015 5K iMac, none of those changes offer a compelling reason to ditch your current system right this minute unless it's earned an "I brake for Netflix" bumper sticker. And if you've waited this long you might also want to think about waiting a little longer until MacOS 10.13 (High Sierra) ships in the fall to save yourself a time-consuming upgrade. Or, if you need something with more power but that's still an all-in-one, you could wait until the end of the year and try the upcoming iMac Pro, which packs considerably more powerful Intel Xeon processors and AMD Vega graphics into a largely identical (but space gray) body.

Still a solid design

The iMac has stood up pretty well over the years and continues that trend. True, it's no longer a system that you can really get excited about as cutting edge, and the static feature set isn't as comparatively impressive as it was when it first shipped. Of course, a lot of that has to do with Apple's no-thank-you stand on newer technologies such as computer touchscreens or wireless charging; that limits the scope of new hardware features it might add. The Retina 5K is still the highest resolution display in an all-in-one, but now it has to compete with larger ones, such as the HP Envy Curved 34-inch, and sufficiently high-resolution-for-most-people 4K models.

In the context of current 27-inch all-in-one designs it's still quite functional and I have no complaints about it, with the exception of the SD card slot on the back. (And the fact that you have to wait for the $5,000 iMac Pro for a UHS-II compatible slot.) But it's starting to look a little tired with its wide bezels around the screen. HP's Envy models look more streamlined and the Dell XPS 27 puts USB connectors and the SD Card slot on the side of the display, a more convenient location. Oh -- and the XPS 27 also manages to pack in a kick-ass 10-speaker sound system.  

Pricing hasn't changed at all for the 27-inch model  -- $1,800 (£1,750, AU$2,700)  for the entry-level version we tested -- which seems on target for what it offers. The base model is a reasonable configuration for the money; if you want something more powerful, I'd probably suggest a big bump to the Pro 580-based model, with a Core i7 and 16GB memory, at $2,700 (£2,610, AU$4,090). For in-between configurations you most likely won't see significant performance increases that merit spending much more, unless it's to switch completely to SSD from the Fusion drive and/or increase the amount of memory, which now goes up to 64GB in the more expensive 27-inch iMac but still 32GB in the entry-level model. 

Apple iMac (27-inch, 2017)

Price as reviewed $1,799, £1,749, AU$2,699
Display size/resolution 27-inch 5,120x2,880 display
PC CPU 3.4GHz Intel Core i5-7500U
PC Memory 8GB DDR4 SDRAM 2,400MHz
Graphics 4GB AMD Radeon Pro 570
Storage 1TB Fusion drive (28GB SSD + 1GB 7,200 rpm SATA HDD); SD card slot
Ports 1 x Ethernet, 2 x USB-C/Thunderbolt, 4 x USB 3 Type-A
Networking 802.11ac, Bluetooth 4.2
Operating system Apple MacOS Sierra 10.12.5


Given the small set of updates, I'll focus on the significant "deltas" -- performance and display quality. I did test drive an external 34-inch curved monitor via the new USB-C connector and it worked, but every monitor is different so it's impossible to generalize from the experience.


Two USB-C connectors replace the old Mini DisplayPort ones, plus there's a fourth Type-A.

Sarah Tew/CNET

Apple has made a big deal out of the increased brightness of the monitor -- 500 nits (candela per square meter) -- but our tests from 2014 show the "old" 5K tested almost that bright, at about 460 nits. (For comparison, most monitors top out around 400 nits.) This one is definitely brighter: it hit peak brightness of 540 nits in my tests. Still, most folks really don't want to use it at 100 percent: that's too bright. (For reference, in photo editing you usually work in the range of 120 to 220 nits.) A higher peak brightness does offer some extra longevity as brightness usually decreases over time. The important level Apple needs to hit next is 1,000 nits, which is in the spec for HDR video.

The display still delivers excellent color accuracy, certainly the best I've seen in an all-in-one and possibly for monitors in its class in general, at least within the Adobe RGB and sRGB gamuts. Much has been made about the increase from an 8-bit per color palette -- referred to as "millions of colors" --  to 10 bits or "one billion" colors. That's not as big of a deal as it seems. Since it's only simulating 10 bits by fooling your eyes, the expansion doesn't help for color-critical, wide-gamut work, which requires a true 10-bit panel, among other things. It was already good enough for everything else.

(Just because a computer can do the math to generate a billion colors and a display can theoretically display any given one of them doesn't change the fact that humans can only differentiate about 7-10 million. The more colors it can display, though, makes it more likely you'll to be able to see differences between two close shades, especially in desaturated greens.)

And while games may look better thanks to the expanded color rendering and higher brightness, until High Sierra comes out with its generally more efficient Metal 2 graphics software interface and optimizations, most speed-intensive gaming will remain a sub-optimal experience. And Macs aren't a key platform for most traditional PC games anyway. When new or noteworthy games do land on MacOS, they're often late, or offer much more limited graphics options.

As for performance, the combination of faster memory, processors and storage results in noticeably speedier operation. The Core i5 system acquits itself well for the essentials, such as streaming video, web browsing, email and so on, and Photoshop seemed pretty zippy working with medium (around 30MB) files. Given the results we've seen from the latest Core i7-based MacBook Pro, I think the Core i7 iMac model will be quite fast for an all-in-one.

A smart choice, but not a no-brainer

If you bought a 5K iMac in 2015 or 2016, there's no need to regret the timing; it will still support the new architectural features in MacOS High Sierra, such as a new file system, and even support for external graphics cards, as well as updated applications like Photos. As an upgrade from a small, slow 21.5-inch iMac or slower 27-inch, or moving from a MacBook, it's still an excellent choice that should last you more than a few years.

Alternatively, if you're looking for something beyond even the new CPU, GPU and memory options here,  Apple's even higher-end iMac Pro is coming later this year, starting at $4,999 (roughly £3,845 or AU$6,715). Though if you're willing to spend that much and don't need workstation-certified components, you could also consider kitting out a top-end iMac 27 for about as much. 

Multimedia Multitasking Test 3.0

Microsoft Surface Studio 171HP Envy Curved AIO 34 (2017) 186Dell XPS 27 (early 2017) 196HP Envy AIO 27 (late 2016) 198Apple iMac 27 (2017) 212Dell XPS 27 (mid 2017) 217
Note: Shorter bars indicated better performance (in seconds)

Geekbench 4 (Multi-Core)

Dell XPS 27 (mid 2017) 15750Apple iMac 27 (2017) 14128Dell XPS 27 (early 2017) 4006HP Envy Curved AIO 34 (2017) 4001Microsoft Surface Studio 3589HP Envy AIO 27 (late 2016) 3724
Note: Longer bars indicate better performance

Cinebench R15 OpenGL

Dell XPS 27 (mid 2017) 115HP Envy Curved AIO 34 (2017) 113Apple iMac 27 (2017) 106
Note: Longer bars indicate better performance (frames per second)

System configurations

Apple iMac 27 (2017) Apple MacOS Sierra 10.12.5; 3.4GHz Intel Core i5-7500U; 8GB 2400MHz DDR4 SDRAM; 4GB Radeon Pro 570; 1TB Fusion Drive Journaled HFS+
Dell XPS 27 (early 2017) Microsoft Windows 10 Home (64-bit); 3.4GHz Intel Core i7-6700; 16GB DDR4 SDRAM 2,400MHz; 4GB AMD Radeon R9 M470X; 512GB SSD
Dell XPS 27 (mid 2017) Microsoft Windows 10 Home (64-bit); 3.6GHz Core i7-7700; 16GB DDR4 SDRAM 2,133Hz; 8GB AMD Radeon RX 570; 512GB PCIe SSD
HP Envy AIO 27 (late 2016) Microsoft Windows 10 Home (64-bit); 2.8GHz Intel Core i7-6700T; 16GB DDR4 SDRAM 2,133MHz; 4GB Nvidia GeForce GTX 950M; 128GB SSD + 1TB HDD
HP Envy Curved All-in-One 34 (2017) Microsoft Windows 10 Home (64-bit); 2.8GHz Intel Core i7-7700T; 16GB DDR4 SDRAM 2,133MHz; 4GB AMD Radeon RX460; 256GB SSD + 1TB HDD
Microsoft Surface Studio Microsoft Windows 10 Pro (64-bit); 2.7GHz Intel Core i7-6820HQ, 32GB DDR4 SDRAM 2,133MHz, 4GB Nvidia GeForce GTX 980M; 2TB HDD + 128GB SSD

Apple iMac (27-inch, 2017)

Score Breakdown

Design 8Features 8Performance 8