The new iMac made Apple’s self-selected deadline of a November release - but only by a margin about as thin as the new computer’s edges. The company started shipping the new 21.5-inch iMac on 30 November and opened up pre-orders for the 27-inch versions of the all-in-one computer on the same day. The 27-inch version of the new iMac won’t start shipping until December, however.

The new, slimmer iMacs were first unveiled back in October during the event that announced the iPad mini. At the iMacs’ unveiling, Apple promised that the 21.5-inch version would start shipping in November, with the 27-inch models to be available the following month. In the meantime customers weren’t able to pre-order the new model, or even purchase the now superseded iMac from Apple.

By shipping on 30 November, the company appears to be keeping that promise. Reports had claimed that the new iMacs had been delayed due to problems with the new screen lamination process that requires high pressure welding. The screen lamination problems were first identified as a challenge by KGI Securities analyst Ming-Chi Kuo back in July. Kuo noted that the new screen lamination process for the new iMac is more difficult with the 27in model, and suggested that as a result it would launch 6-8 weeks after the 21.5in option.

Apple CEO Tim Cook also hinted at challenges during the financial results conference call with analysts. He revealed: “In terms of general shortages, on the iMac we’ll be constrained for the full quarter in a significant way. Part of that is that we’re beginning shipping the 21-inch iMac in November and the 27-inch in December, and so there will be a short amount of time during the quarter to manufacture.”

Cook revealed high hopes for the new all-in-one Mac, but his comments suggest that he doesn’t expect supply to meet demand: “I expect the demand to be robust. We will have a significant shortage there,” he said.

Cook was speaking about Apple’s fiscal first quarter that runs until the end of December. The first quarter of 2013 looks more promising however. Apple’s new iMac could help boost the company’s poor desktop sales, an analyst has said. KGI Securities analyst Ming-Chi Kuo believes the company could see a 434 per cent quarter over quarter increase in desktop computer sales compared to the first quarter of 2012.

Thinner, lighter

Apple hyped the iMac’s 45 percent thinner profile (just 5mm at its thinnest point), and the 4kg weight the computer sheds over its predecessor. The other significant new feature in the updated iMacs is the Fusion Drive option, which couples the speed and performance of an SSD with a traditional hard drive; we tested the Mac mini variant of the drive and were impressed with its performance (see our review on page 64). The build-to-order Fusion Drive costs an additional £200 for 1TB, or £320 for 3TB (the 3TB option is only available for the 27-inch model).

Apple will offer the 21.5-inch iMac with a 2.7 GHz quad-core Intel Core i5 with Turbo Boost speeds up to 3.2 GHz and the Nvidia GeForce GT 640M for £1,099, and with a 2.9 GHz quad-core Intel Core i5 with Turbo Boost speeds up to 3.6 GHz and the Nvidia GeForce GT 650M for £1,249. The 27-inch iMac will be offered with a 2.9 GHz quad-core Intel Core i5 with Turbo Boost speeds up to 3.6 GHz and the Nvidia GeForce GTX 660M for £1,499, or a 3.2 GHz quad-core Intel Core i5 with Turbo Boost speeds up to 3.6 GHz and the Nvidia GeForce GTX 675MX for £1,699.

If you wanted to kit your new iMac out with all of Apple’s build-to-order options, including 768GB of flash storage and 32GB RAM, it could cost you £3,499

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