A major upgrade to the Apple iMac was made today with the introduction of a 5K Retina display for the 27-inch model. See also: iMac with Retina 5K display release date, price and specs.

At an Apple event broadcast from the company's Cupertino campus, a breakthrough in display technology was the focus of a revision to the all-in-one Mac computer.

New iMac with Retina 5K display review: resolution

It shifts resolution from an already high 2560 x 1440 to a staggering 5120 x 2880 pixels. Alongside the upshift in the number of pixels packed into the panel comes improvements to the construction of the oxide thin-film transistor (TFT), and the compensation film above, to regulate how light exits the panel. That should help ensure that when viewed from an angle the image remains consistent.

To power this new panel Apple developed a new timing controller (TCON) with four times the bandwidth of the previous model, able to handle 40 Gbit/s of data flow.

How does this work in practice? In our brief look at the new iMac with Retina display, the effect is every bit as good as seen from the company’s MacBook Pro with Retina display – only writ large across a huge expanse of display. (See also: Apple iPad mini 3 first-look review.)

New iMac with Retina 5K display review: pixel density

Our quick calculations give this panel a pixel density of around 218 dpi, and peering up close we were unable to see any individual pixels. Stood a little further back, it really is photographic, like the richest, most detailed images you'd find in a photo book.

It was a quick demonstration, but we also couldn't perceive any sense of jitter or reduced framerate that you might expect when so many many pixels – 14.7 million of them – are being refreshed many times per second.

Look out for our full review when we'll be checking how the new iMac deals with fast-moving video.

Graphics processing before the image hits the TCON comes courtesy of an AMD Radeon R9 M290X, with 2 GB of GDDR5 video memory. Or you can opt for an AMD Radeon M295X with 4 GB. (See also: Apple iPad Air 2 first-look review.)

A new main processor powers the iMac with Retina display, a quad-core Intel Core i5, and this can also be configured if required with an Intel Core i7 running at 4.0 GHz. As standard you get 8 GB of system memory, which can be user replaced up to 32 GB.

A Fusion Drive of 1 TB capacity comprising PCIe flash drive with 3.5-inch SATA disk comes as standard. Or you can opt for pure flash memory, either 256, 512 or 1 TB.

Other specifications remain the same, although the two Thunderbolt ports also receive a welcome upgrade to Thunderbolt 2 standard. (See also: Apple Mac OS X Yosemite release date, price and new features: Yosemite available to download today.)

New iMac with Retina 5K display review: UK price

Price of the iMac with Retina 5K display starts at £1999 in the UK. Substituting the 4.0 GHz processor brings the price to £2199, and the higher-spec AMD graphics another £200 again. Want to max out the spec with best CPU, GPU, RAM and storage? Get ready to hand over £3519 for what promises to be the most irresistible all-in-one PC on the planet.

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