It's been about 20 months since Apple last updated the non-Retina versions of the iMac (if you don't include the new cheaper iMac which Apple introduced in June 2014). The non-Retina iMacs are still left untouched, but the company has now added a new, cheaper 27in Retina model to its line up. The new Retina model costs £1,599 (the same price as Apple's top of the line non-Retina 27in iMac did previously).

Apple first released the 27in Retina 5K iMac in October 2014, alongside the iPad Air 2, iPad mini 3 and a new Mac mini. When it launched the 27in Retina iMac cost £1,999 and offered a 3.5GHz quad-core Intel Core i5 processor, 1TB Fusion Drive and AMD Radeon R9 M290X graphics. The price of this model has now been reduced by £150 to £1,849.

Read our preview of the 3.3GHz Retina iMac here.

Notably absent from 2014’s upgrade cycle was the rest of the iMac range, with the four original iMacs remaining untouched since they were updated on 24 September 2013. We are still waiting for these iMacs to be updated.

Here, we bring you everything you need to know about when Apple will upgrade the iMac range, including the new iMac's specs, features, UK price and release date.

To discover what we think about the original Retina 5K iMac, take a look at our Retina iMac review. If you are in the market for a new Mac, read our iMac or Mac mini - Mac desktops compared and Best Mac to buy: Mac Buying Guide.

Apple has also introduced new series of 15in MacBook Pro with Retina display

New cheaper Retina iMac launched, price of £1,999 model reduced

On 19 May, Apple added a new 27in Retina iMac to it's line up. You can now purchase a 27in iMac with 5K Retina display with a 3.3GHz processor for £1,599.

This new, entry-level model comes with 3.3GHz quad core Intel Core i5 (we were presuming this was a newer Broadwell chip but it turns out that Apple is still using Haswell as the Quad-Core Broadwell still isn't available), 8GB RAM, 1TB hard drive and an AMD Radeon R9 M290 graphics card. It costs £1,599.

In adding this new 3.3GHz Retina iMac, Apple has removed the 3.4GHz non-Retina iMac from the line up, which was also priced at £1,599. Apparently, people who order the non-Retina £1,599 iMac before the recent update are receiving the new Retina version of that Mac, according to a Reddit post, via AppleInsider. 

Previously the only iMac with Retina display offered a 3.5GHz processor, 8GB RAM, and a AMD Radeon R9 M290X graphics card £1,999. It shipped with 1TB Fusion Drive as standard, which gave users the benefit of a faster flash drive to use alongside the hard drive.

The flagship iMac still offers a 3.5GHz quad core Intel Core i5 appears to be unchanged, 8GB RAM, 1TB Fusion Drive and an AMD Radeon R9 M290X graphics card. It now costs £1,849, £150 less than when it was introduced.

New 27in Retina iMac: Processor

The 27in Retina iMac models still feature Intel’s Haswell processors, rather than the newer Broadwell, suggesting Apple is skipping the much delayed Broadwell processors and waiting for Skylake.

While it's possible Broadwell wouldn’t have made a great deal of improvement to the 2014 models, the fact that Apple has skipped that generation of chips will raise eyebrows. 

Unfortunately the quad-core Broadwell chips that Apple would have required for the iMac models (and the new 15in MacBook Pro models that were also introduced) haven’t yet launched.

All eyes will be on Intel now, as the company gears up to release Skylake, which is what everyone is really waiting for. Hopefully it won’t take Intel another year to release Quad-core versions of Skylake or we will have a long wait for faster Macs.

New 27in Retina iMac: Build to order options

Build to order options on the Retina iMac include a 4.0GHz Quad-core Intel Core i7, for an extra £200 (only in the top of the range model). You can also get 16GB RAM for £160, or 32GB RAM for £480 at the point of sale (it’s nigh on impossible to update RAM later on).

If you wanted to opt for a Fusion Drive instead of the standard hard drive on the entry level model it will cost you an extra £160. Bringing the price of that model to £1,759.

New 27in Retina iMac: Testing

As soon as we can get our hands on the new 27in Retina iMacs we will, and we will be rigorously testing the processor to see how the newer £1,599 iMac with Retina display compares to the previous model which had similar specs for the same price.

The newer iMac appears to have a slower clock speed than the previous £1,599 model (3.3GHz compared to 3.4GHz). We will undertake testing in our lab as soon as we get our hands on the new model.

In the meantime, is Apple also likely to skip Broadwell in the 21in iMacs? Or will Intel get its act together and produce Skylake chips that are suitable for these Macs – untouched since September 2013. Could we see Skylake iMacs in September or October?

Read on for our predictions of when Apple will update the 21in iMac range.

How long has it been since Apple updated the iMac?

If you ignore the £899 iMac and the Retina iMac, which were both introduced in 2014, the last time the iMac saw a proper update was in September 2013 when Apple added the Haswell processor, new graphics, next generation Wi-Fi and faster PCIe flash storage options. Read our review of the 2013 iMacs. You can read all our iMac reviews here.

When will the new iMacs launch?

We think that a new iMac launch will come this summer. The new Macs may appear in conjunction with Apple’s WWDC, which being a pro focused event would be a good location for the news. Read about what else we expect to see at Apple’s WWDC in June here.

Why hasn’t Apple updated the iMac?

We're pretty confident that the reason why Apple hasn’t updated the rest of the iMac range in such a long time is that it was waiting for Intel to release its the Broadwell chips - which were delayed (read more about this below).

New iMac specs: Price

Another important question is how much will the new iMacs cost if, and when, they do launch?

The current line up is priced as follows:

  • 21.5in, 1.4GHz dual-core i5, £899
  • 21.5in, 2.7GHz quad-core i5, £1,049
  • 21.5in, 2.9GHz quad-core i5, £1,049
  • 27in, 3.2 quad-core i5, £1,449
  • 27in, 3.4 quad-core i5, £1,599
  • 27in, Retina 5K display, 3.5 quad-core i5, £1,999

We expect that Apple won’t change the prices when the new models launch, although it is possible that the second generation of the Retina display iMac may come down in price, or that the other 27in iMacs may gain Retina displays and go up in price, more on that below.

Will the other Macs get a Retina display?

There is already a 27in iMac with Retina display, so it is possible that the other 27in models could see a screen update. It is likely that Apple will eventually role out the new display to these 27in models, although it may be biding time while the price comes down.

As for the 21in iMacs, we don’t think these will get a Retina display yet, predominantly because adding a Retina display would make these models significantly more expensive, and we think Apple will maintain their positioning as consumer Macs.

New iMac specs: processor

The new £899 iMac gained a 1.4GHz processor, the Retina iMac runs a xxx processor. Why didn’t the other iMacs get updated?

Everyone has been waiting for Intel’s Broadwell processor to arrive in the iMac, but those new Intel processors have been delayed to such an extent that it is thought that Apple may even be waiting for their successor – Skylark – to launch.

Intel’s next generation of processors, Broadwell, have faced major delays. Anyone awaiting a new iMac or new 15in Retina MacBook Pro should note that while there are now various Broadwell chips beginning to ship, for example the Core-M in the MacBook and the new i5 chips in the MacBook Air models, and the 13in MacBook Pro, the Quad-Core chips destined for the 27in iMac and the MacBook Pro have not yet shipped. Recent reports suggest that these will ship in the second quarter of this year – so hopefully before June.

Broadwell uses the 14nm manufacturing process and is said to consume 30% less power than its predecessor Haswell. That should be good news for battery life on the portable Macs, but also for those Macs with especially power hungry screens.

However, the successor to Broadwell, Skylark is on the horizon, and due to launch in 2015. Skylark will also use the 14nm manufacturing process, but it will bring even greater CPU and GPU performance, along with reduced power consumption. Features of Skylark will include PCI Express 4.0 and Thunderbolt 3.0, which are likely to appear in the Macs that feature those chips.

After Skylark the next round of processors will be Cannonlake, using the 10nm process but don’t expect to see them before 2017.

New iMac specs: storage

We really hope that Apple brings flash storage to the new range of iMacs in the form of a Fusion Drive, like the one added as standard to the Retina 5K iMac.

The current iMac range is crippled somewhat by the slower hard drives that Apple uses. While a hard drive has the benefit of offering more storage – in the case of these iMacs 1TB – it is a lot slower than the flash drives used in all of Apple’s laptops. To the extent that Mac laptops with similar processors will perform better than the equivalent iMac due to the faster SSD drive.

Apple offers a Fusion Drive currently as a £200 build to order option, we think it should be offered as standard in all Apple’s desktops. Alternatively Apple could start to offer flash drives as standard.

New iMac specs: Ports & USB Type-C

Of all the features on the new MacBook, USB Type-C has probably got the most attention - due to the fact that it’s the only port on the MacBook (read why we think the new MacBook doesn’t deserve all the criticism it’s getting).

When that Mac arrived with the single USB Type-C port there was some concern that it might spell the end for Thunberbolt. Given that Apple has strongly promoted this technology, which it describes as “revolutionary I/O technology that supports high-resolution displays and high-performance data devices through a single, compact port,” the company is very unlikely to be planning to drop it, plus as you can see above, Thunderbolt 3.0 is on its way.

The current line up of iMacs features Thunderbolt 1 (with the exception of the Retina iMac which has Thunderbolt 2). Thunderbolt 1 offers 10Gbp/s. Because they weren’t updated in 2014 these iMacs didn’t gain Thunderbolt 2, which offers 20Gbp/s. When it arrives Thunderbolt 3 will offer 40Gbp/s and be able to drive two external 4K displays (or a single external 5K display).

The USB Type-C port is compatible with USB 3.1 and therefore offers 10Gbp/s (double that of USB 3), but it also allows for charging, as it is able to deliver power at up to 100 watts at 20 volts. You are able to charge the MacBook via this port.

However, as yet USB-C only features on the new MacBook. Will it make its way onto the new iMacs? It seems likely that it will, but simply as a replacement for USB 3.0, we defiantly don’t expect it to replace Thunderbolt.

The current iMac line up offers the following ports and standards:

  • Headphone
  • SDXC card slot
  • Four USB 3 prots
  • Two Thunderbolt ports
  • Ethernet
  • Kensington lock slot  
  • 802.11ac WiFi
  • Bluetooth 4.0

New iMac specs: Graphics card

The current line up of iMacs features the Intel HD Graphics 5000 at the entry-level and the next model up offers Intel Iris Pro Graphics. You can expect to see updates to these cards – the new MacBook Pro 13in offers Intel Iris Graphics 6100, for example, so we’d expect this to appear in the iMacs too.

The higher-end iMacs feature NVIDIA GeForce graphics – the 21.5in iMac offers a GT 750M, the entry-level 27in has a GT 755M and the top of the range (excluding the Retina model) offers a GT 775M. The GeForce 700 series have been around for some time now, first introduced back in May 2013, so they could be described as a bit long in the tooth by now. The GeForce 800 series was introduced in March 2014, so even those graphics cards are now a year old. If Apple is going to stick with NVIDIA then it looks like the GT 900 (introduced in September 2014) might fit the bill. There’s a new GT 1000 series on the horizon, but it’s not expected until 2016.

The iMac with Retina display runs an AMD Radeon R9 M290X processor, so it is feasible that Apple might switch from NVIDIA to AMD, as they have in the past. The company may even move to integrated graphics cards, which are part of the motherboard, but if Apple does this it is likely to upset a lot of pro users.

New iMac specs: Design  

Could the design of the new iMacs change in the next generation? The slim unibody of the current style of iMac was introduced in November 2012, prior to that the design hadn’t really changed since 2009 when the Aluminium unibody design in 21.5in and 27in launched. Previous to that the Aluminium iMac launched in 2007 and came in 20in and 24in versions, and back in 2006 Apple launched the Intel iMac with it’s plastic finish, similar in design to the iMac G5 that launched in 2004. Two years prior to that was the lampstand-like iMac G4 in 2002, and in 1998 the original iMac launched.

That’s a change of design every two or three years, so some might think a new look iMac is due. However, we like the look of the current iMac and can’t think of any way it could change for the better, looking back at the generations of iMacs that preceded it, it does look like evolution to this point, we can’t imagine what can follow. Sure it can get thinner, but the weight and dimensions don’t really matter for a desktop machine.

Features some people would like to see probably include an extendable base to the iMac so that you can position it differently – currently it isn’t possible to raise up the iMac for a more ergonomic position. Aside from that people would probably like to see a Retina display come to the rest of the range.

Read our: 2014 iMac with Fusion Drive review and 2014 budget iMac review as well as our iMac Retina review and the review of the 2013 iMacs.