Windows 8.1 vs. OS X Mavericks: Free Upgrade ShowdownWindows 8.1 vs. OS X Mavericks: Free Upgrade Showdown

Windows 8.1: A Visual Tour

In mid-October, Microsoft debuted Windows 8.1 as a free download to current Windows 8 customers. The next week, Apple announced that customers with Macs from as far back as 2007 would be entitled to free downloads of OS X Mavericks, the newest version of its PC operating system.

Each company embraced a more aggressive pricing structure in a gambit to push users toward the newest technologies and services. According to new figures from Web-tracking firm Net Applications, both companies are also seeing immediate returns, albeit in somewhat different ways.

Net Applications found that Windows 8 and Windows 8.1 combined for 9.25% of desktop downloads in October. They combined for 8.89% in September, when the new version was only available as a preview. Windows 8.1 alone snared 1.72% of the desktop market in its first few weeks, while Windows 8 PCs that have yet to be updated comprise the other 7.53%.

[ Still using Windows XP? Watch out for malware. Read Windows XP Malware: 6X As Bad As Windows 8. ]

Together, the two Windows 8 versions increased only .36 percentage points from September, a meager improvement that suggests slow growth outside the installed base. Still, the data includes encouraging signs for Microsoft.

Un-updated Windows 8 machines accounted for 8.02% of the market in September but only 7.53% in October, suggesting that upgrades from current customers -- rather than new sales -- drove movement. Windows 8.1 continues to advance Microsoft's tablet game plan, so Microsoft will need sales to pick up. But the update also includes a number of tweaks to make the OS more palatable to traditional PC users. The October numbers only hint at long-term trends, but they nonetheless suggest that Windows 8.1's changes -- such as the boot-to-desktop mode -- persuaded a significant number of users to take a look.

Net Applications found that OS X Mavericks secured .84% of the market between its Oct. 22 debut and the end of the month. Windows 8.1 had a head start, but with twice the market share, it's clear that Microsoft's newest OS not only gained more users last month, but also did so faster.

Windows 8.1's 1.72% share accounts for 18.6% of the combined Windows 8 tally. This means that among desktop users running a version of Windows 8, almost one in five are now on 8.1. Net Applications found that 10.9% of Mac Users were running OS X Mavericks.

Still, from certain angles, Apple's new offering was the better performer. Windows 8's touch-oriented Start Screen earned a poor reputation among some longtime desktop users. With 8.1 delivering features designed to appease this discontent, many users had incentive to upgrade immediately. The same couldn't necessarily be said of Mavericks. As a relatively evolutionary upgrade, it didn't have Windows 8.1's built-in urgency. That it nonetheless gained so many users so quickly is impressive.

In addition to Net Applications, online ad network Chitika also found evidence of OS X Mavericks' auspicious start. Based on its data, 5.5% of OS X users downloaded and installed the update during its first day of availability.

The Net Applications figures point to other ways Apple's OS has an early edge. Though Windows 8.1 accounts for 18.6% of Windows 8 users, it accounts for only 1.9% of Windows users in general. The upgrade is free to Windows 8 users, but people running Windows 7 or earlier have to pay to upgrade to Windows 8.1. Many of these people own old machines that cannot run the new software. In other words, Microsoft faces challenges in converting longtime customers to its new platform, whereas OS X Mavericks is already on one out of every 10 Macs.

Outside of the showdown between free OSes, the rest of the market unfolded fairly predictably. With 46.42% of the market, Windows 7 remained the top OS overall. Its market share has climbed in recent months because many enterprises are still moving off of Windows XP, which will lose support in April.

With its end date looming, Windows XP continued to drop. It hit 31.24% in October, down from 31.42% in September. The OS represented almost 40% of the desktop market last January, so it's clear many XP holdouts are finally moving on. But with the April deadline approaching, it appears many Microsoft customers still have work to do.

Windows Vista continued to fade into obsolescence. It held onto 3.63% of the market, down from 3.98%.

The top OS X version was Mountain Lion, the predecessor to Mavericks. It kept 3.31% of the market. It held 3.69% in September, before the new version began to eat into its share.

Overall, Macs represented 7.73% of the PC market, up from 7.54% the month before. Windows maintained a dominant 90.66% but has been incrementally losing market share for months. Over the last year, Microsoft's biggest advantage in the desktop market occurred in March, when Windows machines held 91.89% of the field and OS X machines held only 6.94%.

Net Applications derives its statistics from Web traffic, tracking 160 million monthly visits to 40,000 websites.