Apple is to start using Intel microprocessors in its Macintosh computers, severing its long-term chip alliance with International Business Machines (IBM).

Apple said it will begin delivering Macintosh products using Intel microprocessors, the number-crunching nerve centres of PCs, by this time next year and will have all of its Macintosh computers using Intel processors by the end of 2007.

Apple has publicly expressed frustration with IBM for over a year as "Big Blue" has had problems producing enough working versions of its PowerPC 970 chip, which Apple calls the G5.

Also, IBM has yet to produce a version of the G5 that consumes less power and is suitable for use in Apple's laptop personal computers.

Apple's Steve Jobs said the company had looked at its options and concluded switching to Intel made the most sense.

"As we look out a year or two, for many of the products we want to build, the Intel roadmap is just such a better fit," Mr Jobs said.

Intel chief executive Paul Otellini said both companies' strengths "are a little bit different but they're entirely complementary."

Apple's move is a highprofile win for Intel, the world's largest chipmaker, and a blow to IBM, whose PowerPC chips are used in Apple's desktop PCs, as well as to Freescale Semiconductor, the chip supplier for Apple's laptop PCs and the Mac Mini.

While the switch hurts IBM, analysts have said that the tie-up between Apple and IBM, which was initially designed to thwart Intel's and Microsoft's dominance of the PC industry, has never been hugely profitable for IBM.

IBM has won contracts to supply microprocessors for next-generation video game consoles, including the Xbox 360, which is sold by Microsoft, and consoles from Sony Corporation and Nintendo.

Apple controls nearly two per cent of the global personal computer market, but after years of decline it is now gaining on its rivals as its iPod music players have reestablished the firm as a trendsetter in design and software.

Apple said Microsoft and Adobe Systems will make future versions of its Microsoft Office and Creative Suite for the Macintosh that support both Power PC and Intel processors.

The other processor supplier is Advanced Micro Devices.