Apple iMac Pro review: The most powerful and desirable all-in-one ever – with a price to match

The iMac has always had a consumer-friendly image, ever since the original bulbous “jellybean” design. However, it’s found its way into serious professional roles too, thanks partly to Apple’s superb screen technology. The 27in 5K iMac, in particular, has become a favourite of creative industries and, at first glance, you might think the iMac Pro is a mere minor reworking of that well-loved design.

That’s no bad thing. The iMac has always been one of the coolest computers on the market, with its minimal, super-clean design, and the iMac Pro’s Space Grey tone lends it gravitas without otherwise upsetting the formula.

If you look closely, you’ll spot a few changes at the rear, notably a 10Gbits/sec Ethernet socket, plus fixings for a wall-mount, but overall it’s a study in understatement. The real news is inside the case.

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Apple iMac Pro review: CPU and internals

You might think the high-end iMac models are powerful, but the iMac Pro is in a different league. You won’t find boring old Core i7 CPUs here: instead, you’re looking at a range of bona fide workstation-grade Intel Xeon W processors.

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To be specific, the model we tested has a 3.2GHz Xeon W-2140B processor, with eight cores capable of servicing 16 threads. If that’s not enough power for you, you can go for a 3GHz ten-core model, a 2.5GHz 14-core chip – or a monstrous 4.3GHz 18-core CPU.

As you’d expect, such meaty innards are backed up by serious quantities of RAM. This model comes with 32GB of 2,666MHz DDR4 RAM, which you can spec up to 64GB or 128GB if you like – and it’s of the ECC variety, to provide the stability that professionals demand.Storage meanwhile, comes in the form of a 1TB SSD, which again can be upgraded at the point of purchase to 2TB or 4TB. And let’s not forget the graphics: you can choose between an 8GB AMD Radeon Pro Vega 56 or a 16GB Vega 64 card.

Needless to say, this sort of hardware comes with a professional-grade price tag. The entry-level model – the one we tested – costs an eye-widening £4,899. That makes the top-end 5K iMac look positively cheap at just £2,249. If you really need the 4.3GHz, 18-core machine with 128GB of RAM, a 4TB SSD and a Radeon Pro Vega 64, expect to shell out a smooth £12,279.

Apple iMac Pro models

Apple iMac Pro review: Performance

It must be said, not everyone needs this much power. If you’re editing 1080p video, or doing anything more lightweight than that, the iMac Pro is overkill. It’s aimed at 4K and 8K workflows and not just monoscopic video, but 3D content and 360° VR editing, too.

To put its performance into context, we started by running the iMac Pro through our regular benchmark suite, testing everyday image-editing, video-editing and multitasking workloads. As you’d expect, it demolished its 5K sibling: with an overall score of 281, it proved more than twice as fast as the 27in iMac 5K, which is, to be fair, what you’d hope for from a machine that’s more than double the price.

However, while the iMac Pro is certainly fast, it trailed a long way behind a similarly priced workstation based on the 18-core Core i9-7980XE processor. That’s because this benchmark prioritises multithreaded performance; if your workload relies primarily on core count, a Core i7 or i9 CPU might be a more cost-effective choice than a Xeon.

I saw similar results when we tried downsampling a 4K video to 1080p, using Adobe Premiere’s High Quality 1080p preset. Using OpenCL hardware acceleration, the iMac Pro took 6mins 45secs, while a Core i9-powered rival completed the job in just 2mins 50secs. Indeed, the iMac Pro was slower even than a Core i7-7820X-based workstation costing “only” £2,500 – and switching to Metal hardware acceleration shaved a mere five seconds off the iMac Pro’s rendering time.In the CPU-based Cinebench rendering test, however, the iMac Pro gave a much stronger showing. With an overall score of 3,577, it was barely behind the Core i9 workstation, with its score of 3,867. It’s also worth mentioning that, even with its Xeon CPU taxed to the limit, the iMac Pro remained perfectly quiet, with no distracting fan noise – certainly not something every rival workstation can claim.

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Of course, this isn’t a gaming system, and when it came to real-time 3D graphics we found that the iMac Pro put in a good, rather than great, performance. In Unigine’s Heaven benchmark, it averaged 48fps at 2,560 x 1,440 resolution and medium detail – only a slight improvement over the 5K iMac’s result. If you need more graphical grunt, however, you’ll shortly be able to hook up an external GPU via one of the iMac Pro’s Thunderbolt 3 ports.

And when it comes to storage performance, the iMac Pro excels. The 1TB NVMe SSD is actually made up of two solid-state banks, working in parallel, and the result is lightning-fast read and write speeds: the BlackMagic disk test measured sequential write rates of 3,003MB/sec and reads rates of 2,487MB/sec. That’s comfortably ahead of any individual M.2 SSD we’ve ever tested and it’s worth mentioning that this is with full-disk AES disk encryption, courtesy of Apple’s new T2 security chip.

Apple iMac Pro review: Display

With its native resolution of 5,120 x 2,880, the iMac Pro’s 27in IPS display is precisely as fantastic as the older 5K iMac’s. Out of the box, it comes calibrated for the DCI-P3 colour space and our in-house colorimeter confirmed that it was spot on, reproducing 98.9% of the DCI-P3 gamut. It’s tremendously bright and bold too, with a searing maximum brightness of 551cd/m² and a contrast ratio of 1,044:1.If pushed to criticise, I’d have to say that the gloss finish isn’t ideal for all lighting environments, although its anti-reflective coating does a fair job of keeping glare to an acceptable minimum. The bezel looks a little on the large side too, in a world where laptops and phones are increasingly moving to “all-screen” fronts.

Still, those are minor quibbles with what is overall a stunning display. And, if you somehow find you need even more workspace, you can use the Thunderbolt 3 connections at the rear to attach two additional screens, also at resolutions up to 5K.

Apple iMac Pro review: Verdict

The iMac Pro is a hugely impressive machine. It’s faster than any previous Mac, with exceptional connectivity and storage performance. And while it’s certainly expensive, the price does include a professional-grade DCI-P3-calibrated 27in monitor – which would set you back several grand on its own.

Of course, there’s a premium to pay for the design and, as you bump up the specs it gets less and less competitive. If you’re on a tight budget you’ll unarguably get more bang for your buck from a custom-built Windows-based system coupled with a separate professional monitor.

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But the iMac Pro isn’t just a computer, it’s an inspiration. For years, graphic designers have chosen the clean, stylish all-in-one iMac as the perfect platform not only for their workflows, but for their physical workspaces. Now, those working in heavy-duty visual roles can do the same.

To complain about the price, therefore, or the fact that big-box workstations may still have the edge when it comes to performance, is to miss the point. There’s simply nothing else out there like the iMac Pro – and for its target market it’s a wholly irresistible step forward.