21.5in iMac (2019) vs MacBook Air (2018) full review

The MacBook Air has always been one of Apple’s most popular Macs, but when Apple failed to update it for over three years everyone thought that the Air had breathed its last. When in October 2018 Apple updated the MacBook Air there were celebrations aplenty. The new MacBook Air has all-new, smaller and thinner design, new colour options, and a Retina display. And best of all, it costs £1,199/$1,199.

However, the MacBook Air isn’t the most powerful Mac you can get for that price, and you may end up missing some of the features it lacks. Find out what you can get for about the same amount of money if you buy one of Apple’s new 2019 iMacs.

Here we will compare the entry-level MacBook Air with the £1,249/$1,299 iMac - that’s not the entry-level iMac (which costs £1,049/$1,099) because we don’t recommend the entry-level iMac on account of it being over priced considering it has not been updated since 2017 and lacks a Retina display. Nor are we suggesting that you buy the older MacBook Air that Apple still sells, that model costs £949/$999, but is not a good deal.

MacBook Air


Before the MacBook Air was updated in 2018 there were rumours that Apple would be pricing it at under £1,000/$1,000. This didn’t happen - aside from Apple keeping the older model on at that price.

A new MacBook Air costs £1,199/$1,199. For that you get a 1.6GHz dual-core 8th-generation Intel Core i5 processor with Turbo Boost up to 3.6GHz, 128GB SSD storage, Intel UHD Graphics 617 and a Retina display. There’s a second MacBook Air available for £1,399/$1,399 but the only difference is that it offers 256GB storage. You can buy a MacBook Air from Apple here.

The 2019 iMac starts at £1,249/$1,299. What do you get for spending £50/$100 more? You get a 3.6GHz 8th-generation Intel Core i3 Quad-Core processor, 1TB Storage, a Radeon Pro 555X graphics card, and a Retina 4K Display. You can buy an iMac from Apple here.

There’s no doubt that the iMac offers better value for money, but there are disadvantages - the most obvious one being that you can’t carry it around with you. But if you are looking for a good value Mac to use at home or in the office, then the iMac represents good bang for your buck.


The iMac has had the same design for more than a decade. It’s a nice design, but, as we mention in our reviews of the 2019 21.5in iMac and 27in iMac, the iMac would benefit from a few changes to the design. We’d like to see smaller bezels around the screen so that the screen could be larger without the dimensions having to change much. We’d also like the screen to be more adjustable so that you can position it on your desk in an ergonomically friendly way. 

Massive bezels on iMac

The MacBook Air had a complete redesign in 2018, although it’s still got the trademark wedge shape that tapers to a smaller point, thereby keeping the laptop light and giving the impression that it is thinner than it is. It’s not as small and light as the MacBook, but as laptops go, it’s one of the most attractive laptops you can buy, and comes in Gold, Silver and Space Grey.

MacBook Air

What it all comes down to is whether you need to be able to carry the computer around with you or if it will always be located in the same place. If you don’t need to be able to move it the iMac will be a good option, but if you will be carrying it to and from work or university then it has to be a laptop.


Both the iMac and the MacBook Air have Retina displays (with the exception of the £1,049/$1,099 iMac and the older £949/$999 MacBook Air).

The iMac display is superior predominantly because it is bigger, but there is more to it than that.

The MacBook Air screen measures 13.3in. The display is LED-backlit and uses IPS technology. It has a 2560x1600 native resolution at 227 pixels per inch. And it supports millions of colours.

The iMac screen measures 21.5in. It offers 4,096x2,304 resolution (4K) and supports 1 billion colours. This is the most vibrant Retina display you can get on a Mac.

You may find the screen on the MacBook Air cramped for working on if you often have a lot of windows open. We have a 13in MacBook Pro to work on and always use it plugged into an external monitor. You could also plug your MacBook Air into an external monitor but note that it has only two USB Type C ports, one of which is required for charging.

MacBook Air

The iMac screen, at 21.5in is probably a better size for working on, it would also be great for watching films and slide-shows on.

Features & Specs

There are various differences between the iMac and the MacBook Air in addition to the obvious fact that one is a laptop and the other a desktop. Here we'll look in more detail at the components, explaining why one is a better choice than the other.


The iMac we are looking at here has a 3.6GHz quad‑core Intel Core i3 eighth-generation processor.

The MacBook Air has a 1.6GHz dual-core Intel Core i5 eighth-generation processor. This sounds worse than the one in the iMac, and it is. There are two processors here compared to the four in the quad-core iMac. However, the MacBook can Turbo Boost up to 3.6GHz, while the iMac, due to it using an i3 chip, can’t Turbo Boost to get extra power when needed.

The quad-core processor in the iMac is always going to beat the MacBook Air though.


The MacBook Air comes with 8GB of 2133MHz LPDDR3 RAM as standard, and can be configured to take 16GB.

Like the Air, the iMac comes with 8GB of RAM, but in this case it is 2400MHz DDR4 memory, which is faster. There are also iMacs available with even faster 2666MHz memory. The iMac is configurable to 16GB or 32GB RAM.

If you think you are going to want to update the RAM in your Mac in the future the best option for you would be the 27in iMac, which costs a lot more than the 21in version, but has a hatch on the back that can be opened so that you can add more RAM (as seen in the image below). If you want to add more RAM to the 21.5in iMac it can only be done via an Apple authorised service provider. It's impossible to add more RAM to the MacBook Air.

iMac RAM hatch


If you were thinking the 1TB of storage in the iMac is an advantage you are wrong.

It might look good on paper that the iMac comes with a 1TB hard drive but that’s a 5400-rpm drive that will slow the Mac down considerably. Our advice here would be to switch from the hard drive to a Fusion Drive, a build-to-order option that costs an extra £90. That will give you the same 1TB storage, but you will also have a small SSD that can store things so that they can be accessed quickly. This will speed up operation.

Alternatively an even better solution is to opt for a 256GB SSD inside your iMac - a £180 build-to-order option - and get an external hard drive or pay for iCloud if you really think you need the extra storage. 2TB iCloud storage costs £6.99/$9.99. Here’s how much iCloud costs.

The MacBook Air on the other hand offers a 128GB PCIe-based SSD with options to configure it to 256GB, 512GB or 1.5TB SSD. While 128GB storage might not sound a lot, it has an advantage simply because it’s an SSD.

With a SSD you will get better performance and faster boot-up time. A hard drive will give you more GB of space for your money but there are many disadvantages, including the fact that because there are moving parts they can be noisy, they fail more often than SSDs, magnets can erase the data, and they require more power.

The most obvious difference: with an SSD or Fusion Drive your Mac will start up almost instantaneously. With a hard drive you might as well go and make a cup of tea while you wait for it to start up.


The MacBook Air comes with an Intel UHD Graphics 617. That’s a graphics card that is integrated onto the processor and shares memory with the system.

The iMac has a discrete graphics card which has its own memory. So you will have a better experience with games and any graphic intensive apps.

iMac 21.5in screen

But do you need a discrete graphics card like the one inside the iMac? If you are going to be playing games on your Mac then the iMac’s a better bet - but you might actually want to consider spending a bit more to get a superior iMac with an even better graphics card.

Alternatively, if you really needed better graphics for your MacBook Air you could plug in an external GPU, but at around £600/$600 we doubt that is a feasible solution for many.

But if you are just going to be using your Mac to surf the web, edit your photos and make the odd home movie, write an essay, or input data in a spreadsheet, then a discrete graphics card isn't going to be essential.

Ports & Peripherals

When it comes to ports the Air is limited with just two Thunderbolt 3 (USB‑C) ports, one of which needs to be used for charging.

Air ports

The iMac, on-the-other-hand, has two Thunderbolt 3 (USB‑C) ports, four USB 3 ports, one SDXD card slot and Gigabit Ethernet.

Thanks to the Thunderbolt 3 ports the MacBook Air can support one external display with 5120x2880 resolution at up to 60Hz, or up to two external displays with 4096x2304 resolution at up to 60Hz.

The iMac can go one better though, offering support for one 5120x2880 (5K) external display at 60Hz with 1 billion colours, or two 3840x2160 (4K UHD) external displays at 60Hz with 1 billion colours, or two 4096x2304 (4K) external displays at 60Hz with millions of colours.

Back of iMac

Both the MacBook Air and the iMac have a 720p FaceTime HD camera. Don’t expect this camera to be as good as the one on the front of your iPhone though.

Finally, both the Air and the iMac support 802.11ac Wi‑Fi wireless networking; IEEE 802.11a/b/g/n compatible, Bluetooth 4.2 wireless technology.


The MacBook Air has the advantage of being a lightweight laptop that you can carry around, and it comes with an SSD, so you don’t have to spend extra upgrading it so as not to be lumbered with a slow hard drive.

But, if what you want is the most powerful Mac you can get for your money then the iMac is a better option. The £1,249 iMac (or £1,339 iMac if you add the Fusion Drive as we recommend) is significantly more powerful than the MacBook Air. It also offers more ports, better graphics, superior RAM, and a faster, quad-core processor.

However, there’s one other option to consider if you are looking for a powerful Mac and you are happy to choose a desktop. The Mac mini, which we compare to the iMac here, costs £799/$799 for an identical 3.6GHz quad-core 8th-generation Intel Core i3 to the one in the iMac. The mini benefits from a 128GB SSD, but lacks the discrete graphics of the iMac, and doesn’t come with a display. Despite that, at £450/$450 less than the iMac you may well want to consider it.

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