That was fast.\nNew data from Net Applications, a U.S. analytics firm, suggests that users have taken a shine to Windows 10: Microsoft's new OS ended last week powering a record 3 percent of all Windows devices.\nBack of the envelope calculations show that 3 percent figure represents approximately 45 million systems. That's in line with Windows 7's uptake rate during its first few weeks of availability in 2009, and is notably larger than Windows 8's growth rate three years later. According to Net Applications data, Windows 8 didn't hit the same 3 percent milestone until late February 2013, four full months after it debuted.\nWindows 10, which is critically important to Microsoft after the lackluster reception for its predecessor, was officially released July 29.\nDigging into the data from Net Applications shows that:\n\nThe percentage of all PCs online that were running Windows 10 during the week of Aug. 2-8 -- better known as user share -- was 2.7 percent. Windows 10's user share of systems running some version of Windows was the slightly higher 3 percent during the same week. (The two numbers don't match because Windows overall runs on 90 percent of PCs, with Apple's OS X and Linux running on the bulk of the remaining systems.)\nThe latest user share figure was dramatically higher than the week of July 26-Aug. 1, the period that included the launch of Windows 10, first to Insider testers, then to those users who reserved a copy from their Windows 7 or Windows 8.1 machines.\nWindows 10's rise came, not surprisingly, at the expense of Windows 8.1, which during the same three-week stretch fell from 13.7 percent of all Windows devices to 11.9 percent. That's a 13 percent decline. Other versions of Windows fell, too, though not as fast. Windows 7, for instance, dropped 1.5 percentage points.\n\nWith Windows now running on an estimated 1.5 billion devices worldwide -- that's the figure Microsoft has repeatedly talked up -- the 3 percent attributed to Windows 10 would represent more than 45 million systems.\nNet Applications measures operating system user share by tracking unique visitors to the websites which use its analytics platform.\nWith reports by Gregg Keizer at Computerworld.