Apple 21.5in iMac (3.6GHz, 4-core, 2019) vs Apple 21.5in iMac (2.3GHz, dual-core, 2017) full review

There are new iMacs for 2019 but what's changed since the last generation and should you upgrade? We explain everything you need to know when it comes to the differences between the 2017 and 2019 iMacs.

Apple left the iMac range for almost two years before refreshing its all-in-one desktop so there must be some big changes right? Well yes and no.

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


In old-school Apple fashion, the new iMacs have arrived with no price increase so if you were about to order the older one but held off then you're in luck.

That means the 21.5in model starts at £1,249/$1,299 and the 27in is available from £1,749/$1,799.

It's worth noting that not all the 2017 models have been discontinued. So the cheapest iMac at £1,049/$1,099 might be tempting but it has dated specs and you should avoid getting it. If you want a different 2017 model, then you'll need to look in Apple's refurbished store.

Here's a quick run down of the current models on available from Apple:

iMac 21.5in

  • 2.3GHz dual-core 7th-gen Intel Core i5, 8GB RAM, 1TB HD, Full HD display - £1,049/$1,099 (2017)
  • 3.6GHz quad-core 8th-gen Intel Core i3, 8GB RAM, 1TB HD, Retina 4K display, Radeon Pro 555X -  £1,249/$1,299
  • 3.0GHz six-core 8th-gen Intel Core i5, 8GB RAM, 1TB Fusion Drive, Retina 4K display, Radeon Pro 560X -  £1,449/$1,499

Read our 2019 21.5in iMac review here.

iMac 27in

  • 3.0GHz six-core 8th-gen Core i5, 8GB RAM, 1TB Fusion Drive, Retina 5K display, Radeon Pro 570X -  £1,749/$1,799
  • 3.1GHz six-core 8th-gen Core i5, 8GB RAM, 1TB Fusion Drive, Retina 5K display, Radeon Pro 575X -  £1,949/$1,999
  • 3.7GHz six-core 9th-gen Core i5, 8GB RAM, 2TB Fusion Drive, Retina 5K display, Radeon Pro 580X - £2,249/$2,299

Read our review of the 27in iMac here


There's very little to say here because the iMac hasn't had a design change at all this year. The desktop has had this slim design since 2012 so is overdue a physical update but that's not the case just yet.

We'll have to wait a bit longer for Apple to get rid of the big chin and perhaps make the screen height adjustable.

iMac 2017 rear

Specs and features

It's what's underneath the shiny iMac exterior that's changed this year, with a pretty major hardware refresh including new processors, graphics cards and ram.

Before we explain what's new, let's clarify the things that have stayed the same since 2017. You get the same 4K or 5K Retina Display for the 21.5in and 27in models respectively (ignoring the 2017 model that's still on sale).

You also get a FaceTime HD webcam, stereo speakers and the same set of ports. They include four USB-A ports, two Thunderbolt (USB-C) ports and Ethernet.

So the big news here is that there are new 8th and 9th-gen Intel processors ranging from a quad-core i3 all the way up to an octa-core i9. Most standard models have a six-core i5 of varying clock speeds.

Now, there's 8GB of RAM across the board but you can configure the iMacs to higher capacities now. The 21.5in goes to 32GB and the 27in goes all the way up to 64GB should you need it. It's also faster than before at 2400- or mostly 2666Mz.

There's also a new range of AMD graphics cards with no less than seven different cards available across the range. So the 2019 iMac comes with at least at Radeon Pro 555X with 2GB of VRAM and goes all the way up to a (configurable) Radeon Pro Vega 48 with 8GB of VRAM.

Of course, the performance gain will depend what model you're moving from and to. However, we've tested some 2019 models and saw some sizeable jumps. Check out the chart below to see the difference with newer models in blue.

Last but not least, here's a specs table to give you an overview of the specs differences between the 2017 and 2019 iMacs.

  iMac 21.5in 4K (2017) iMac 21.5in 4K (2019) iMac 27in 5K (2017) iMac 27in 5K (2019)
Display 21.5-inch, 4096x2304  21.5-inch, 4096x2304  27-inch, 5120x2880  27-inch, 5120x2880 
Processor 7th-gen Intel Core i5 dual-core or i7 quad-core 8th-gen Intel Core i3 quad-core, i5 or i7 six-core 7th-gen Intel Core i5 dual-core, i5 or i7 quad-core 8th/9th-gen Intel Core i5 six-core or 9th-gen Core i9 octa-core
Graphics 2GB AMD Radeon Pro 555 or 4GB Radeon Pro 560 2GB AMD Radeon Pro 555X, 4GB Radeon Pro 560X, 4GB Radeon Pro Vega 20 4GB AMD Radeon Pro 570, 575 or 8GB Radeon Pro 580 4GB AMD Radeon Pro 570X, 575X, 8GB HBM2 580X or Radeon Pro Vega 48
Memory Up to 32GB 2,400MHz Up to 32GB 2,666MHz DDR4 Up to 64GB 2,400MHz Up to 64GB 2,666MHz DDR4
Storage 1TB 5,400 rpm HDD, 1TB Fusion drive, 256GB to 1TB SSD 1TB 5,400 rpm HDD, 1TB Fusion drive, 256GB to 1TB SSD  Up to 3TB Fusion drive or up to 2TB SSD Up to 3TB Fusion drive or up to 2TB SSD
USB-A 4 4 4 4
Thunderbolt 2 2 2 2
Webcam FaceTime HD FaceTime HD FaceTime HD FaceTime HD


You might be waiting for a design change, but for now you'll have to be content with a jump in performance. Of which there is a decent jump on offer from the 2017 models.

If you're 2017 iMac is feeling a little sluggish then an upgrade could be well worth it. If you're deciding between the 2017 and 2019 models then we strongly advise avoiding the older model that's still on sale.

If you don't need the power of the new 2019 hardware, then a bargain may be found by grabbing a refurbished 2017 model.

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