Apple iMac 27-inch (2020) review: More pro than ever

After the dream of announcing that it will move future Macs to its own custom made, Arm-based processors, it only took a month for Apple to show us that the near future is very much Intel-based.  

The iMac is 21 years old and has already seen one processor transition, so another in the future is just par for the course. But the jury is very much out on whether Apple's own processors will match the power of its current crop of machines.

While at one time the iMac was an entry-level machine that's no longer the case. The 27-inch model on review here comes with 3.4GB/s read and write SSD storage as default, while it's got 6-core processors as a minimum.

Atlhough this iMac doesn't quite have the power of the Mac Pro or iMac Pro, it's still very much a 'pro' in its delivery. 

Design

• Dimensions (27in): 516mm x 650mm (stand is 203mm of height) / Weight (27in): 8.92 kg
• Available in 21-inch and 27-inch models
• Same design as predecessor

The appearance of the iMac still stuns those who are not used to it, whether they're behind the display or in front of it. Not that it's changed at all compared to its predecessor. 

Yep, the iMac hasn't changed externally. Rumours of a smaller-bezel iMac have abounded in 2020, but the hardware hasn't emerged. It would be surprising if this same design lasts when at least some versions of the iMac has Apple Silicon in 2021 or 2022.

Not that we're expecting a change to angle-poise days, but we reckon we'll see a thin-bezel design next. That's not a great leap, to be fair, but it's a step forward. 

It's that bezel that dates this iMac - especially the one up top - because when the display is on those black bars are more noticable than should be the case in 2020. We're seeing more and more monitors and all-in-ones offer thin-bezel displays. Still, the design as it is isn't a deal-breaker and the iMac's slimline form still impresses.

Display

• 5K display: 5120 x 2880 resolution, wide colour gamut (P3), 500 nits brightness
• Nano-texture glass option for bright environments

The new iMac still has the same 5K display as before, resplendent with 14.7 million pixels and 500 nits of brightness - so it punches well in all lighting conditions. This is partly because this time it uses Apple's tried and tested True Tone technology designed to adjust to your surroundings and match the ambient light. 

There's a little enhancement available this time, too, provided you're willing to spend an extra $500/£500 for the pleasure – nano-texture glass. For that outlay, the glass is etched at a nanometre level to diffuse light. 

Also seen in Apple's incredible Pro Display XDR, this textured glass option is designed for glaring environments where you need to minimise screen reflections. The display is still glossy to a certain extent - though significantly less so than iMacs without it - but get up close and you'll see a subtle matte finish which is also designed to avoid fingerprints. 

We have this feature on our test model and we used it in different lighting environments to try and replicate what it would be like under harsh lighting. We really couldn't get it to glare at all. OK, so we're at home at the moment (like pretty much everybody), but even under bright spotlights and with strip lighting we couldn't get too much of a kickback from the display. In our office there's a large window with bright sunlight (not the location pictured above) and the sunlight really didn't make much of an impression at all.

We even got a torch and shone it directly at the screen. The light just appears dulled, so it is highly effective and is something we've grown to really appreciate over our week with this iMac. Whether that equates to $500/£$500 worth of effectiveness will be a matter of professional choice.

There is one disadvantage: nano-texture glass could be damaged by using anything to clean the display other than a soft cloth - which is unceremoniously included alongside the keyboard and mouse - because it really is uncoated, etched glass and, therefore, you don't want to mess with it too much.

There's one more thing to say about the iMac display in general - and that is that the Mac is still vehemently non-touch. That's still cool in a pro-environment. But it's no longer cool for a 27-inch computer that a family interacts with at a home.

Performance

• Intel Comet Lake 10th Generation Core i processor options
• AMD Radeon Pro 5000 series graphics options
• Storage to 8TB; RAM to 128GB

Intel's 10th Generation Core i processors (Comet Lake) are here under the hood in 6- and 8-core variants of the Core i5 and i7. It's even possible to upgrade to an epic 3.6Ghz 10-core Core i9-10900K that'll Turbo Boost to 5GHz - this is what we have in our test model - and, as you'd expect, this absolutely flies.

Comparing it using Geekbench 5 to the previous high-end iMac CPU - the 8-core Core i9-9900K - there's a small uplift in single-core performance, but with multi-core you get around 25-30 per cent increase in performance. It's even a better score than the base-level Intel Xeon-powered iMac Pro from 2017.

Apple set itself an interesting challenge when heralding the upcoming switch to Apple Silicon - both in terms of continuing to launch and sell Intel Macs and for itself. If it manages to produce processors with this level of performance in the next two years then wow - that's some impressive work given Intel's pedigree, even if it's crystal clear that Intel's move to 7nm chips is not going well.

What is also crystal clear is that, if you need an iMac, you shouldn't waste your time waiting around for an Apple Silicon version to appear because you could be waiting until 2022. 

The build-to-order options are numerous and you can max out at 8TB of storage and a huge 128GB of RAM (double what you could get before). As before RAM is user upgradeable through a panel on the back should you want to get it at a later date from elsewhere. In terms of graphics, the Radeon 5300 remains the standard option in the range. 

We've got the top-notch AMD Radeon Pro 5700XT in our test model, alongside 32GB of RAM and a 1TB SSD (plus the nano-texture glass) which adds $1,700/£1,700 to the price - giving you a nice round $3,999/£3,999. Max out the RAM and SSD and it's now possible to spend over $8,000/£8,000 on an iMac. Wow.

Performance-wise, the 5700XT graphics is clearly an improvement on last year's model. There has been some chatter online that the XT gets a little on the toasty side, but we only found the area around the stand where the fan grille is got warm under heavy loads - and that's when the iMac's fan will kick in. This fan isn't as noisy as many, but is still noticeable. Even so, it's more of an elegant woosh than an old school MacBook Pro helicopter take-off. 

The SSD speeds are hugely fast. Using Blackmagic Disk Speed Test we got write speeds of around 2,400MB/s and read speeds of upwards of 2,600MB/s. That's pretty nuts - comparable with figures we've seen for the 16-inch MacBook Pro and over double the speed of the SSD inside the 2020 MacBook Air. 

Audio, webcam and more

• Upgradeable LAN port
• New Full HD (1080p) webcam 
• Improved speakers and three-mic array

Good audio quality has always been an iMac strength. Apple has improved the audio system in this iMac and the speakers are loud and generally crisp. Bass is particularly impressive - though we noticed that past three-quarters volume things tend to get a little distorted with an average source such as streaming internet radio.

But at that volume, it's actually too loud to sit in front of anyway - you need to move further away! Of course you'll want to pair with speakers or AirPlay/Bluetooth elsewhere if you're particularly concerned about sound quality, but 90 per cent of the time you really won't need to. 

The triple microphone array first seen in the 16-inch MacBook Pro includes one on the rear of the iMac's chassis for noise-cancelling - and we found this worked excellently for video calls. We were told we came across very clearly.

One thing that has definitely changed from previous models is the webcam – yes, really. Apple has decided to bring 1080p quality to the fore, rather than 720p. It's a welcome change and is something that has been needed for some time – it was particularly galling to still get a 720p camera on the 16-inch MacBook Pro. And it's very good for video calling as you can see above.

What the camera won't do in this iMac is to enable you to use Face ID. Though that is clearly destined to come to the Mac at some point, we think it'll be a feature reserved to make a splash for Apple Silicon Macs.

The camera's image quality is helped by Apple's inclusion of its T2 chip inside the 27-inch iMac - which assists exposure and tone mapping as well as face detection to keep your face in focus and well-lit. Even on a dull day it didn't look like we were sitting in the dark. It also enables the 'Hey Siri' feature in addition to encrypting the contents of the iMac's SSD.

Coincidentally, there's also a somewhat expensive $100/£100 build-to-order option to upgrade the Ethernet port to 10GB Ethernet, though only particular power users connected to a workplace LAN will need that. Once again there's a really good selection of ports including dual USB-C/Thunderbolt 3, four USB-A, SD card slot and audio out. And yes, it's still annoying having to reach around the back to plug things in and out. 

This iMac is probably the last Mac to ship with macOS 10.15 Catalina and indeed macOS 10 (goodbye OS X, it's been a couple of decades) as macOS 11 Big Sur is just around the corner and will be a free upgrade once released. Big Sur is a little more iPad-like in design but looks great and it seems well positioned to usher in the next generation of Mac.