Apple 27in iMac (3.1GHz, 6-core, 8th-gen, 2019) full review

The iMac is twenty-one years old in August 2019. We had been hoping for a redesign of the iconic all-in-one desktop Mac to mark the occasion. Sadly that is not to be, but there are some significant changes to what’s on the inside. And it’s what’s on the inside that counts, right?

The 2019 27in iMac has more powerful processors with 6-cores (and an 8-core build-to-order option), improved graphics cards (including the Radeon Pro Vega) and faster RAM, making it a much more impressive machine than its 2017 equivalent.

In this review we are looking at the bottom of the range 27in iMac, with its 3.0GHz 6-core 8th generation i5 processor. We have a separate review for the 21.5in iMac with the same processor but a different graphics card. We’ve also benchmarked the build-to-order 3.6GHz 8-core 9th-generation Intel Core i9 model which could be seen as competition for the iMac Pro.

Note: a new 27in iMac has launched for 2020, for more information read: How the 2020 iMac compares to the 2019 iMac.


The 2019 iMac pricing remains the same, in fact, pricing hasn’t changed here in the UK since Apple adjusted it in October 2016.

Here's how the pricing of the 2019 27in iMac breaks down:

  • 3.0GHz 6-core 8th-gen i5, Retina 5K, 1TB Fusion Drive, 8GB 2666MHz RAM, Radeon Pro 570X (+4GB memory), £1,749/$1,799
  • 3.1GHz 6-core 8th-gen i5, Retina 5K, 1TB Fusion Drive, 8GB 2666MHz RAM, Radeon Pro 575X (+4GB memory), £1,949/$1,999
  • 3.7GHz 6-core 9th-gen i5, Retina 5K, 2TB Fusion Drive, 8GB 2666MHz RAM, Radeon Pro 580X (+8GB memory), £2,249/$2,299

You can buy the 27in iMac from Apple here, or have a look at our best iMac deals article to see if you can pick up a bargain.

Build-to-order options:

  • 3.6GHz 6-core 9th-gen i9 processor + £360/$400
  • 16GB RAM + £180/$200
  • 32GB RAM + £540/$600
  • 64GB RAM + £900/$1,000 (only available for the 3.1- and 3.7GHz models)
  • 512GB SSD + £270/$100
  • 1TB SSD + £630/$500
  • 2TB SSD + £990/$1,100 (only available for 3.7GHz model)
  • Radeon Pro Vega 48 with 8GB HBM2 memory +£405/$450 (only available for 3.7GHz model)

(Upgrade prices are for the top-of-the-range model, similar upgrades might cost more for the other models.)

We have also looked at the 21.5in iMac with the same 3.0GHz 6-core processor as features in the entry-level 27in iMac. This is an interesting comparison because, you could save £300 and get an almost identical iMac. The main difference being the smaller 4K screen and a slightly less powerful graphics card. In this review we’ll look at whether it would be a wise choice to save or spend that £300/$300.


iMac 2019 review

The 2019 iMac looks just the same as it did back in 2012 when Apple slimmed down the aluminium iMac design. Even in 2012 the design didn’t change significantly from the original Aluminium iMac that was introduced back in 2007, or the unibody Aluminium design of 2009, if you are being pedantic. This is the longest Apple has gone without refreshing a product’s design.

But does the lack of physical change really matter? The iMac is a beautiful looking computer, perhaps Apple chief design officer Jonathan Ive got the design so spot on ten years ago that nothing needs to change on the outside.

However, the design does have its faults. We, like many others, position our iMac on top of a hardback book in order to have the screen at an ergonomically-friendly height. This is necessary because it is not possible to adjust the height of the screen, beyond tilting it to face upwards or downwards very slightly.

The screen is probably the iMac's most striking feature, and yet, around the screen are inch-wide bezels and at the bottom a 2.5in aluminium section. Apple’s been reducing the bezels on the MacBooks, the iPhone and the iPad and we’d love to see Apple slim the bezels down to accommodate a larger display on the iMac.

If you measure the entire screen diagonally it’s 29.5in. If Apple reduces the bezels we could conceivably see a 30in iMac display in the future.

Bezels on the iMac

As the tech inside the iMac gets more powerful it will get hotter. When Apple introduced the powerful iMac Pro in 2017 it was necessary for Apple to make some changes on the inside in order to incorporate the necessary cooling system. To make room for these changes Apple only ships the iMac Pro with an SSD and does not offer a Fusion Drive option. 

In the future we expect to see similar changes to the standard iMac, but clearly Apple’s not felt it was necessary to do so yet. Read about what we expect from the 2020 iMac here.


There is more to the screen than how it looks, of course. Back in 2014 Apple added a 5K Retina display to the 27in iMac. Since then the 5K Retina has offered 5,120 x 2,880 pixels, compared to 4,096 x 2,304 on the 21.5GHz 4K iMac.

2017 brought even more improvements to the Retina display and those are carried over to the 2019 version, which boasts 500nits and 10-bit dithering. That basically means that the screen is 43 per cent brighter than the pre-2017 iMac, and capable of reproducing even more colours: a total of 1 billion to be exact.

That 5K display is actually higher-resolution and better quality than the screens used by most designers. Some might balk at the fact that Apple opts to match the DCI-P9 colour space, meaning the display can only output about 92% of the Adobe RGB colour space, however, it is incredibly accurate according to tests (which our sister site, Digital Arts performed with a DataColor Spyder5Elite.)

So, the screen is a good reason to upgrade if your existing Retina iMac is pre-2017. And if you are using a non-Retina screen currently, then prepare to be astonished - this is one of the best 5K screens you can buy.


The 2019 iMac has some impressive specs, specifically an upgraded processor, better graphics card and faster RAM. Beyond that are some stellar build-to-order options that go some way to close the gap between the 27in iMac and the iMac Pro.


The 2019 27in iMacs benefit from two generations of processor options. The entry-level and mid-range models offer 8th-generation Coffee Lake Intel processors, which is an upgrade from the 7th-generation Kaby Lake processors in the 2017 iMacs and jump from four- to six-cores.

The top-of-the-range 27in iMac features a 9th-generation processor - which is still Coffee Lake, but is able to accommodate additional cores compared to the 8th generation - up to eight-cores (octa-core) in the build-to-order option.

We have benchmarked the 3GHz 6-core 8th-generation entry-level 27in model and the build-to-order 3.6GHz 8-core 9th-generation iMac. We also looked at the 3GHz 6-core 8th-generation 21.5in iMac - which is a useful comparison with the 27in as while the processor is the same the graphics card is different. We also have data for the iMac Pro, all of which can provide a clearer picture of where the iMac falls in the Apple lineup.

The 8th generation processors are from 2018, but the 9th generation Coffee Lake Refresh processors were introduced in January 2019.

The processors are as follows:

  • 3.0GHz 6-core 8th-gen i5, i5-8500 (same processor as the one inside the £1,449/$1499 iMac and £1,099/$1,099 2018 Mac mini.)
  • 3.1GHz 6-core 8th-gen i5, i5-8600.
  • 3.7GHz 6-core 9th-gen i5, i5-9600KF.
  • 3.6GHz 8-core 9th-gen i9, i9-9900KF (build-to-order).

As you’d expect the Geekbench multi-core scores for the 27in 3.0GHz processor and the same 3.0GHz processor in the 21.5in iMac were very similar. 20,890 for the 21.5in compared to 20,943 for the 27in. This is already a superior score to that seen from the 2017 equivalent models, where we saw 14,106 and 14,017.

However, the most impressive score came from the 3.6GHz 8-core 9th-gen i9 processor, here we saw 33,484 which compares very favourably to the 33,638 we saw from the iMac Pro. (Note we ran the Geekbench tests on the older iMacs back in 2017, so there could be discrepancies due to the different version of macOS and the different version of Geekbench, but this should give a good indication of the speed bump you can expect).

As we mentioned in our review of the 2019 21.5in iMac, the 3.0GHz 6-core processor shared by the entry-level 27in and the top-of-the-range 21.5in model is also shared by the 2018 Mac mini. Unfortunately we haven’t tested that Mac mini, so we can’t confirm our suspicions that the processor score may turn out to be higher on the Mac mini thanks to the SSD, however, we do have the scores for the 3.2GHz 6-core built to order option on the Mac mini (24,670), and the 3.6GHz quad-core Mac mini (14,453).

Based on this, we think it’s likely you will see a decent speed bump if you exchange the Fusion Drive that comes as standard in the iMacs for an SSD. We’ll talk more about the storage options below.

We also ran the Cinebench R20 CPU test. Unfortunately, because this is a new benchmark, we can’t compare the previous generation’s score (which used an earlier version of Cinebench). However, we do have the equivalent scores for the build-to-order 3.6GHz 8-core i9 and the iMac Pro which makes for an interesting comparison.

For the 27in 3GHz, 6-core, 27in iMac, with 570X Graphics, we saw a Cinebench R20 CPU score of 2,382 compared to 2,364 for the 3GHz, 6-core, 21.5in iMac, with 560X Graphics. The 3.6GHz 8-core 9th-generation Core i9 iMac we also had on test scored 4,265 in this test.


Alongside the processor the other major change inside the 2019 iMac is the graphics card - which is the main difference between the 3.0GHz 21.5in and 27in iMacs.

Here we see a boost from the Radeon Pro 570 with 4GB video memory in 2017’s £1,749/$1,799 model to a Radeon Pro 570X with 4GB memory in the 2019 model; a boost from the Radeon Pro 575 with 4GB in 2017 to the Radeon Pro 575X with 4GB memory in the £1,949/$1999 2019 model; and from the Radeon Pro 580 with 8GB memory to the Radeon Pro 580X with 8GB in the top-of-the-range £2,249/$2,299 model.

In addition, there is a build-to-order option of a Radeon Pro Vega 48 with 8GB memory (for £405/$450 - this option is only available on the top-of-the-range iMac).

It used to be that only the 27in iMacs offered discrete graphics card options, which would have been a good reason to choose the larger model over the smaller. However, in 2017 all models bar the entry-level 21.5in gained discrete Radeon Pro graphics cards, so, it is no longer necessary to choose a 27in iMac to take advantage of superior graphics. The 27in models do offer better graphics cards than the 21.5in models though, so expect to see better scores in graphics related tests.

We ran the new Cinebench R20 CPU tests as mentioned above. With this new test Maxon is focused on the CPU, but based on heavy graphic use. 

With a view to getting an even closer look at the graphics capabilities, we ran the Open GL and Metal Geekbench graphics tests. We did see some interesting differences between the slightly different graphics cards used in the otherwise identically specced 3.0GHz 21.5in and 27in iMacs.

iMac 2019 review

In the Geekbench Compute Open CL tests we saw 64,202 for the 21.5in with its Radeon Pro 560X with 4GB compared to 88,014 for the 27in with its Radeon Pro 570X with 4GB memory. We saw a similar leap with the Geekbench Compute Metal test, a leap from 63,487 for the 21.5in to 92,489 for the 27in iMac. The leap you see with the Radeon Pro Vega 48 in the build-to-order i9 iMac with 3.6GHz 8-core processor is astonishing: 143,010 for the Metal test and 137,943 for Open CL.

We also ran the Unigene Valley benchmark, and in that case we do have comparable scores from other Macs (although it’s worth noting that these benchmarks were performed in older versions of macOS).

This is where you can really see the difference between the iMac with its discrete graphics and Mac mini and its integrated graphics. The score is double what the 6-core 3.2 Mac mini saw, and considerably higher than the 2017 equivalent. The X might look like a minor difference in generations, but you can expect a decent boost.

If you are running graphics-intensive apps then these discrete graphics options will be very attractive. The 27in iMac offers the best graphics options - and is the only option if you want the Radeon Pro Vega 48 - but they don’t represent the huge leap from the 21.5in iMac that they used to.

Now, the 21.5in iMac offers the same Radeon Pro 555X and Radeon Pro 560X as the 15in MacBook Pro, which is considered by many to be a great option for creative pros. Chances are the bigger 5K screen will more than justify your choice to get the 27in rather than the 21.5in iMac though.

2019 iMac 27in review


There’s one final change between the 2017 and 2019 models. Apple has tweaked the RAM from 2400MHz to 2666MHz. Every 27in iMac gets this new, faster RAM but only the top-of-the-range, 3.0GHz 21.5in model does.

In real terms this improved RAM will give users an increase in speed because it is able to transfer data faster and process operations quicker.

If you are looking for a reason to choose the 27in iMac over the 21.5in iMac, the fact that RAM is easily upgradable in the 27in iMac thanks to a hatch on the back is likely to sway you.

Ram hatch 2019 iMac

Officially the RAM inside the 21.5in iMac can’t be updated, but that’s not entirely true. In 2017 iFixit noted that rather than being soldered onto the motherboard, the RAM inside the 21.5in iMac is located in a RAM hatch behind the logic board, so it is accessible, but it’s not something we’d recommend trying at home. We assume that Apple hasn’t soldered the RAM in place in 2019, but Apple definitely hasn’t made it any easier to assess the RAM in the 21.5in model, so, for now, the 27in iMac is the best option if you think you might want to upgrade the RAM at some point in the future.

Speaking of RAM upgrades, the 27in iMac can take up to 64GB RAM, but only in the £1,949 and £2,249 models, not the entry-level 27in iMac that we looked at, which maxes out at 32GB RAM.


The storage options haven’t changed, but they are worthy of note because they are one of the biggest disadvantages of the iMac range - if you need 1TB then you may have to settle for a slower hard drive rather than stump up an extra £630 for the faster 1TB SSD.

Apple’s solution to the problem of slow hard drives is the Fusion Drive, which combines a 1TB hard drive with a little SSD so that some things can load from the SSD, and therefore appear instantaneously, and others can be stored on the hard drive. A Fusion Drive is a faster option than a standard hard drive (like the one found in the entry-level 21.5in iMac) but a SSD will be an even faster option.

It’s our opinion that probably you don’t need 1TB of storage so much that it justifies being lumbered with a 5400-rpm hard drive, even if there is a SSD included with it - and that SSD is about 24GB, smaller than when Apple first introduced the Fusion drive. We think that hard drive will undo all the good work of the other components inside the iMac, so upgrade to an SSD, you can choose a 256GB SSD for £180/$200, and if you really need more storage then get an external drive or use iCloud (2TB costs £6.99/$9.99 per month).

We ran a storage benchmark on the two iMacs with Fusion drives we were evaluating as well as the 27in build-to-order model that came with a 512GB SSD. Just look at how much better the SSDs perform in the Mac mini and the MacBook Pro models compared to the slower iMac Fusion Drives. It's odd that the SSD in the 27in iMac seems to perform less well than that in the MacBook Pro and Mac mini though.

It’s also worth noting that in 2017 Apple improved the SSD storage, claiming it was 50 percent faster, with write speeds of 3Gbps. So if you have an iMac with an SSD from before 2017, you will experience a boost in comparison.

Ports & Peripherals

There is no change here from the 2017 iMac, although if you are upgrading from an earlier model then you’ll be gaining two Thunderbolt 3 ports (which double up as USB Type-C ports).

In addition, you will find four USB-A ports, like the kind used on the iPhone charger and sorely missed from all Apple’s laptops bar the older MacBook Air model. It might be old tech, but many of us still have mice and keyboards that we want to plug in to our Mac.

Back of the 27in iMac


The 2019 27in iMac is impressive and the build-to-order options, such as the 8-core 9th generation Intel processor and the Radeon Pro Vega 48 graphics card are first-class. Out only real criticism is that there is less of a gap between the 21.5in and 27in iMac than there used to be, which is great news to anyone who wants all that power for less money, but when it comes to the 27in iMac you get the feeling that you are paying a lot more to get the bigger screen.

Is the 27in display worth an additional £300? It is certainly beneficial if you have a lot of windows open, or if you need work on an image at a very high magnification, or use Final Cut Pro for multichannel editing, for example. The 5K display on the iMac is as good, if not better than any other 5K display out there - and it costs considerably less, and comes with a computer. If you need the bigger screen then it’s definitely worth the extra expense.

There is also the fact that only the 27in iMac offers 64GB RAM, the Vega graphics card, and the 9th-generation Intel processors.

We are disappointed that Apple hasn’t given the iMac a new look though. The iMac hasn’t changed its appearance since 2012, and the aluminium iMac arrived even longer ago in 2009. This would be forgivable if the iMac design was perfect, but it isn’t. The wide bezels are a waste of space and the screen can’t be positioned ergonomically. If a 27in iMac screen is beautiful imagine what a 30in iMac screen would be like.

If you need a new iMac now then the 2019 updates bring it in to line with the MacBook Pro with up to six-cores, faster RAM, and better graphics cards. If you can hang on for another year or two we are hoping for a new iMac with reduced bezels and an even bigger screen, surely that’s not too much to ask.

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