Driven by millions of upgrades, Windows 8's global usage share climbed by a third last month, but the new OS's adoption pace remained lethargic compared to that of its predecessor three years ago.
According to data released Thursday by Web measurement firm Net Applications, 0.45% of all computers running Windows during October were powered by Windows 8. That number, which represents 45 out of every 10,000 Windows machines, was a jump of slightly more than one-third over the month before.
But it's a far cry from Windows 7's uptake: At the end of October 2009, Windows 7 accounted for 2.33% of all Windows PCs, or 233 out of 10,000. That puts Windows 7 as the easy winner in the early race. Its share of all Windows PCs in its release month was more than five times that of Windows 8's.
There is at least one caveat, however. Windows 7 went on sale Oct. 22, 2009, four days earlier on the calendar than Windows 8, which hit retail Oct. 26.
Windows 8's jump, small as it was in absolute terms, could be attributed to the large number of upgrades sold so far. On Tuesday, Microsoft CEO Steve Ballmer said that the company had sold 4 million upgrades to Windows 8 Pro in the first three days of availability.
Last Friday was the first day that customers could download the $39.99 upgrade to Windows 8 Pro, take advantage of a $14.99 deal if they had purchased a new Windows 7 PC starting June 2, or pick up a DVD in a boxed copy for $69.99 at retailers.
New PCs, tablets and so-called "convertibles" -- systems that share characteristics of a light notebook and a tablet -- also went on sale Oct. 26, all with Windows 8 pre-installed.
Windows 8's October gain was its best-ever since Net Applications began tracking the new operating system, but it's fallen further behind Windows 7's pace. In 2009, Windows 7 added 0.69 of a percentage point during its release month, a jump of about 40%. Windows 8, however, added just 0.12 of a percentage point, less than a fifth as much.
In fact, Windows 8 will have to hustle to match the uptake of Windows Vista. That problem-plagued edition accounted for 1% of all copies of Windows after its first full month. To equal that, Windows 8 will have to more than double its share during November.
Other versions of Windows stuck with their long-established trajectories.
Windows XP lost six-tenths of a percentage point last month, but still accounted for 40.7% of all personal computers, or 44.4% of all Windows machines. Vista also dropped, falling by a quarter of a point to under 6% for the first time since July 2007.
And Windows 7 gained ground, adding about seven-tenths of a point to end the month with a 44.7% share of all PCs and a 48.8% of all Windows PCs. At its current pace, Windows 7 will break the 50% mark next month to become the edition used by a majority of Windows customers.
That trend will likely continue, analysts have said, as enterprises continue to replace their aged Windows XP hardware with newer machines running Windows 7, not Windows 8.
The poor-thus-far showing of Windows 8 doesn't preclude it from eventually thriving, of course. Microsoft is reportedly ready to spend between $1 billion and $1.5 billion on advertising the new operating system, its Windows RT spin-off, and the also-new Windows Phone 8.
At his company's BUILD developers conference, Ballmer made clear that Microsoft was betting big. "You will not be able to pick up a magazine, go to the Internet or turn on a television set without seeing one of our ads," Ballmer told developers Tuesday.
Net Applications measures operating system usage by tracking unique visitors to approximately 40,000 sites it monitors for clients.
See more Computerworld Windows 8 launch coverage including news, reviews and blogs.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His email address is email@example.com.