Inside the 5K iMac

new iMac

What's inside the astonishing new 5K iMac, announced on Thursday? K.Stewart reports

When Apple said they were shipping the 5K Retina, they weren’t kidding and iFixit and has already opened one up on its site . As is typical of Apple when delivering a technological leap, they’ve minimised risk where possible with a chassis and components mostly unchanged from last year.

Unlike the new Mac mini’s, RAM is easily upgradeable through a dedicated hatch. It’s even possible to upgrade the socketed CPU and HDD/SSD storage - although the practicalities of removing that huge 27-inch 5K screen to get inside is for determined DIYers only.

Apple’s custom TCON chip for driving the 5K display is married to a broader than usual data connection cable, plus a display board with a host of Texas Instrument chips.

In terms of performance, it should be noted that Apple provided their flagship iMac with the option of the 4GHz Core i7-4790K - basically the fastest Haswell CPU for most single-threaded tasks. Moreover, it doesn’t lag behind the Mac Pro in multi-core performance as much as you might expect. Geek bench comparison here; The graphic card options are, however, still chosen for the slimline chassis more than performance - laptop rather than desktop class.

The overall performance matters because if you move away from its proprietary video connections - to say a Mac Pro - then driving a 5K display would equate to DisplayPort 1.3 and Thunderbolt 3 with Intel’s Skylake chip. That’s to say, the CPU shipping after Broadwell… This also means it’s not possible to drive that 5K iMac screen with an external computer.

Dell’s imminent $2500 5K display gets around this issue by using a pair of Thunderbolt 2 ports to drive the screen, but until it’s shipped and tested, there’s no way to know how well that will work and the price is, of course, on a par with the iMac screen (which comes with a computer included).

Consequently, more than a few Mac Pro owners are giving the iMac a long hard look. Marco Arment is one of those jumping ship and he makes a good case why on his blog.

The thermal constraints of an iMac built for looking good versus a Mac Pro built around a cooling system shouldn’t be forgotten, however, and a Mac Pro update should be imminent. Intel ‘Grantley’ Xeon 3 v3 processors are due to ship soon, while AMD’s FirePro graphics cards are being refreshed - which should mean an update for the custom range used by Apple. This could give the Mac Pro a significant performance boost, but there may yet be a long wait for an Apple 5K Cinema Display.

Read our coverage of Apple's announcements here