The changes to the Mac are the most significant, though. Apple will release a major new version of the Mac operating system, called Big Sur, with support for the new chips. The design looks similar to the iPhone and iPad, with curved app icons, translucency, notification bubbles and the new widgets feature from iOS 14.

The Messages and Maps apps will gain many of the features available in their mobile counterparts, and the Safari web browser will get a translation tool, changes to tabbed browsing and a customisable homepage. Apple executives made a point of showing how smoothly these apps run on Apple-designed chips.

The partnership between Apple and Intel was formed in 2005, when Steve Jobs outlined a move away from PowerPC processors onstage at the same Apple event series for developers. Intel helped Apple catch up to Windows-based computers, some of which were more powerful at the time. In tandem, though, Apple was working on more energy-efficient chips for mobile devices based on Arm designs and continues to use those to power the iPhone and iPad.

In recent years, the speed and power efficiency of Apple’s mobile chips have rapidly increased, while the pace of improvement to Intel’s parts has slowed. This irked Apple executives, who pushed the company’s silicon unit to develop more powerful processors fit for the Mac, people familiar with the matter have said.

The split from Intel has been a long time in the making. As far back as 2012, Apple was exploring a switch to its own chips, Bloomberg reported at the time. In 2018, Bloomberg reported that Apple would formally begin the transition away from Intel in 2020.

In addition to ensuring legacy software runs well on the new Macs, a challenge for Apple will be to make processors speedy enough to replace Intel chips in its “pro” line of computers. Apple did not say on Monday which models will get the new chips. Intel shares were about flat in intraday trading, while Apple’s stock was up 2 per cent on Monday, surpassing marketwide gains.

Intel said in an emailed statement that it will continue to support Apple as a customer. Intel also boasted that its chips are the most advanced and offer the most open platform for software developers.

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The Mac is no longer the key revenue driver for Apple that it once was, but it safely sells about 20 million units a year, delivering about US$25 billion in revenue. The computers are also key for Apple to retain its professional market, which helps spur purchases of more popular devices like iPhones, AirPods and Apple Watches.

For Intel, a break with Apple is more of a symbolic blow than a financial one. The entire Mac laptop line-up represents less than 5 per cent of Intel’s annual revenue, according to an estimate by Stacy Rasgon, an analyst at Sanford C Bernstein. The bigger concern is that Apple could embolden other computer makers to make similar moves, he said. “Now you have an actual PC that can run on something that’s not Intel.”

Intel, the world’s largest chip maker, has shrugged off attempts to unseat its dominance of personal computing for decades. Its only direct rival at present is Advanced Micro Devices (AMD), which has produced newer processors that have begun to take share over the last two years. But AMD’s revenue is still less than 10 per cent of Intel’s.

Other efforts to break Intel’s lucrative grip on computer processors have not made much of a dent. Microsoft has a version of Windows that works with chips made by Qualcomm. Personal computer makers, including Microsoft itself, have made laptops based on that combination. Those products are praised for their battery life, but have not grabbed significant market share. The Qualcomm processors are based on the Arm technology that Apple uses in its semiconductors.

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While Intel’s grip on the market is largely intact and its earnings continue to grow, analysts have seen signs of slippage. Most of that stems from persistent delays in introducing new production techniques. Once the leader in the crucial means of making processors faster and more efficient, Intel now trails Taiwan Semiconductor Manufacturing Co, the producer of all Apple-designed chips.

Those slip-ups may have accelerated Apple’s departure from Intel, said Matt Ramsay, an analyst at Cowen & Co. Apple is a technology leader partly because of its control over both the software and hardware and its willingness to replace suppliers when it spots a vulnerability or an advantage elsewhere.

“Their reputation with suppliers is of being somewhat ruthless,” said Ramsay. “It looks like another consequence of Intel’s execution challenges.”