Apple 24in iMac (2021) M1 vs Best iMac (2021) full review

The iMac is, perhaps, the most famous Mac of all. First introduced in 1998, Apple's all-in-one Mac has evolved through various different forms, from the original clear plastic and bold coloured CRT monitor to the most recent design change which brought colour back to the impossibly flat screened frame.

There is a sort of limbo right now, with three different types of iMac available to choose from: Apple's sells a 21.5in iMac with an Intel processor, the new 24in iMac with Apple's own M1 chip (read our M1 iMac review), and the 27in iMac (review) which, for now at least, has an Intel processor. These three Macs might share the same name, but they couldn't be more different.

Luckily we're here to help you decide which of Apple's iMacs will be best for your needs.

We'll start by outlining the features and specs of each of the iMacs Apple sells, and the build-to-order options that could help you create the Mac you need.

Should you buy the 21.5in iMac?

Apple's cheapest iMac starts at £1,099/$1,099. It has a 21.5in display which, crucially, is not Retina quality. Apple did sell 21.5in iMacs with 4K Retina displays, but these are no longer sold by Apple - although you may find one in Apple's Refurbished Store, or at another retailer (see our iMac deals round up).

This display offers just 1,920x1,080 pixels, which isn't a lot when you consider that the 4K display offers 4,096x2,304 pixels and the new 4.5K 24in iMac display offers 4,480x2,520 pixels. It's also not as bright and doesn't offer the colour range of the other iMac displays. Needless to say, if you are looking for an iMac because you want something to view photos or movies this isn't going to fulfill your needs.

21.5in iMac

The screen isn't the only thing letting down the 21.5in iMac. The processor is a 2.3GHz dual-core i5 from Intel, which already sounds pretty low-power, but it gets worse: it's a 7th-generation Intel Kaby Lake processor that Apple first used in 2017. Kaby Lake itself was introduced in 2016. So here we have a five year old processor in a Mac with a poor quality display. It's hard to find a good reason to buy one.

Probably there are a couple of reasons why people buy the 21.5in iMac. One is the fact that the 21.5in iMac offers four USB-A ports, while the entry-level 24in iMac only offers USB-C ports. For anyone who has various peripherals with the older USB-A connection this may seem to be an important feature. However, there are 24in iMac models that also offer the older style USB port, so the port is not a significant reason to choose the 21.5in iMac.

The only reason left to choose this iMac over any other is the lower price of £1,099/$1.099. Except it's not a great price. £150/$200 more will get you the entry-level 24in iMac. £400/$400 less will get you a Mac mini with an Apple M1 chip.

So, basically, this is not the Mac to buy - unless you find a really good deal (check the latest deals below for the £1,099/$1,099 iMac).

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So what is the best iMac?

Should you buy the 24in iMac?

Apple offers three 24in iMacs, but actually it all breaks down to two different options: an entry-level model with 8-core CPU with 7-Core GPU, two USB 4/Thunderbolt ports and a Magic Keyboard with Lock Key for £1,249/$1,299. Or a 8-core CPU with 8-Core GPU, two USB 4/Thunderbolt ports and two USB 3 ports (which will take those old USB A cables) and a Magic Keyboard with Touch ID for £1,449/$1,499.

24in iMac

There are plenty of good reasons to opt for the more expensive model, if you can afford to.

Probably the most obvious difference is the choice between seven or eight graphics units (GPU). If you pick the iMac with one less GPU you can expect a slightly worse performance in graphics-intensive applications. In our tests we could see that the additional GPU does make a reasonable difference to the Mac's performance. But the secret here is that there's more at play here than an extra GPU core - the 8-core GPU model also has a second fan. This serves to stop the Mac from overheating when under strain. The flip side is that the one-fan Mac will slow down - or be throttled - to stop it overheating when it's working particularly hard. Hence the entry-level 24in iMac is slower than its sibling despite having the same M1 chip with the same amount of processor cores. Read: Cheapest 24in iMac only has one fan.

So, the message here is that it's worth opting for the extra graphics core, even if you don't use graphics-hungry applications.

The other difference between the two types of 24in iMac is the keyboard. The new colourful iMacs feature a keyboard that complements the colour of the iMac, but the keyboard that ships with the entry-level 24in iMac has a Lock Key where the keyboard that comes with the more expensive model has a Touch ID key.

The Magic Keyboard with Touch ID is actually available as a build-to-order option with the entry-level 24in iMac, but the option is well hidden. You need to click on "Change to another keyboard" and then you can choose the Touch ID version for an additional £50/$50. This additional cost already puts you part of the way to the full cost of the better model though, and we'd suggest that playing another £150/$150 extra to get that extra GPU core and fan would be money well spent.

Read: Why you should get the Touch ID keyboard with the 24in iMac.  We also have How to buy the Magic Keyboard with Touch ID.

However, price is what lets down the 24in iMac. It's just so expensive when you compare it to the Mac mini, which has the exact same specs but just lacks the display. If it was just a couple of hundred difference in price this wouldn't be such an obvious drawback, but we are talking £550/$600 difference between the entry-level models of the two Mac varieties. We find it hard to justify the extra expense when we could buy a decent 4K display and still have money to spare. Read: Mac mini vs iMac.

This poor comparison with the Mac mini (review) leads us to conclude that the 24in iMac is simply overpriced, as is often the case with all-new Mac models.

But perhaps you are prepared to pay the extra because the beautiful design combined with the stunning display are worth the extra outlay, and that's a perfectly good reason to choose the 24in iMac - we'd just suggest you pick the £1,449/$1,499, the best deals for which are below.

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Should you buy the 27in iMac?

There is one other iMac you can choose from. The 27in iMac is an all-in-one iMac designed, and priced, for pro-users. It offers discrete graphics, a 5K Retina display and powerful Intel processors. The 24in iMac, as good as the M1 Chip is, is not really going to meet the needs of the typical user of the 27in iMac (we'll explain why below).

The 27in iMac was last updated in August 2020, so it's just a year old now, and its days are likely numbered, with a replacement model no doubt in the pipeline at Apple. The rumours indicate this new iMac will have a bigger screen and a pro-level Apple chip, but we don't know how long we will have to wait for that - we estimate that it will arrive in spring 2022. So for now if you are a pro-user looking for a Mac desktop the 27in iMac is one to consider.

27in iMac

Here's how the 27in iMac compares to the best of the 24in models:

The 27in iMac starts at £1,799/$1,799, in contrast you can spend £1,449/$1,499 or £1,649/$1,699 on the 24in iMac. The fractionally lower price does little to make the 24in iMac a more attractive proposition, in many ways it lends weight to our conclusion that the 24in model is overpriced for what it is.

The 27in iMac is, of course, more expensive than the 24in iMac, but it has a number of pro-focused features in its favour including 6-core or 8-core (or build-to-order 10-core) 10th generation Intel processors, the option to add up to 128GB RAM (while the 24in model maxes out at just 16GB RAM), and high-end Radeon Pro graphics cards.

The M1 Chip is impressive, and as you can see from our CPU benchmarks, it does beat the 2020 8-core processor in the 3.8GHz 27in iMac.

But when it comes to graphics performance there is no denying the advantage of the Radeon Pro graphics, which are leagues ahead. The M1 is good, but not that good.

The other factor in favour of the 27in iMac is the 5K retina display, although the 4.5K Retina display of the 24in model is closing the gap. Both offer 500 nits brightness, Wide colour and True Tone, but the 27in model with its 5,120x2,880 pixels is clearly ahead of its sibling's 4,480x2,520 pixels. We expect that whatever Apple is developing as a replacement for the 27in iMac will make that gap even wider, of course, so you may wish to wait for that.

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For more information read Should I buy a 27in iMac now or wait?

Which iMac is best?

The right iMac for you is going to depend on a number of factors: your budget, your needs and how urgently you need to have one right now.

If you don't have an unlimited budget then we would suggest that rather than purchasing one of the Macs Apple is selling right now you maximise what you can get for your money by purchasing a discontinued 21.5in or 27in iMac at a discount. We are always on the look out for the best iMac deals and we often see really great discounts on iMacs that Apple no longer sells. You could purchase a discontinued 21.5in iMac, with discrete graphics and a decent Intel processor for less than the 24in iMac. ;

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If you love the new 24in iMac design then we would suggest that you spend a bit more to buy one with 8-core GPU.

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And if you need the ultimate iMac, the August 2020 27in iMac is still a good option, despite being a year old now and destined for replacement. It's still the best value option for anyone who needs a Mac capable handling the most demanding graphics.

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For more advice about which Mac to buy read the following:

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