Throughout their history, Intel and the x86 architecture for which it is known have played a pivotal role in the platform war between Apple and Microsoft.
IBM's decision to use Intel chips for the original IBM PC led to Microsoft supporting that landmark computer, and Windows grew on the back of backward compatibility with DOS apps that ran on those chips. Years before Windows RT, which runs on ARM processors, Microsoft tried to move beyond Intel by supporting other processors with Windows NT, but those versions were discontinued.
Apple, meanwhile, couldn't take advantage of many apps that required x86 processors (especially games). A partnership with Motorola and IBM to create a credible rival to Intel with PowerPC collapsed even after it took jabs at the Pentium's heat output. Advantage: Microsoft
In 2006, following its struggles to get a PowerPC G5 into its laptops, Apple finally switched to processors from Intel, which had now gotten power-efficiency religion. The switch brought an interesting side benefit. Macs could now dual-boot into Windows -- or even run it simultaneously with OS X using software from VMWare and Parallels -- even though it required the purchase of a full Windows license. Still, the move accelerated the Mac's growth despite the difficult transition, putting it on a path to creating the ultrathin MacBook Air that spawned the ultrabook push. Advantage: Apple
More recently, faced with increasing competitive pressure from ARM, Intel has become even more fanatical about extending its processors' power efficiency. This has been dramatically proven by its latest Haswell processors found inside the new MacBook Air. In the 13-inch model, battery life has been extended from seven hours to 12 hours (some tests have found it to last longer), finally enabling a longstanding industry holy grail of all-day battery life in a sleek form factor.
But while Apple clearly gains from these improvements, Microsoft and its partners may gain even more, at least on a relative basis, The promise of 10-plus hours on a screen of 10-plus inches enables an ultrathin notebook, tablet, or mutation running Windows to rival the running times of today's tablets while retaining backward compatibility. These PC industry stakeholders have been betting big that the PC can adapt to cover the range of usage scenarios that Apple's MacBook and iPad lines do, but in a single device. In other words, Haswell could enable something with the battery life of Surface RT with the power and -- more importantly -- backward compatibility of the Surface Pro.
It's not a complete victory for Microsoft. Just as such a combination would put more competitive pressure on Apple and Android tablets, it would put more pressure on ARM-based Windows RT devices, at least in the short term, Again, though, competitive tablets rely far more on the differentiation of ARM chips than Microsoft and other PC companies do.
Indeed, Windows RT will never take off until there is a critical mass of touch-centric apps. These won't be built until developers can latch onto the huge sales volumes of Windows 8 and its Intel-targeted successors.