Microsoft is on a roll with Windows 8. The company’s CEO, Steve Ballmer, announced that the devices and services giant has sold more than four million upgrade licenses for Windows 8 in the three days that the OS has been on the market. Ballmer revealed this impressive statistic during the keynote for the BUILD conference, which is being held at Microsoft’s main campus in Redmond this week.

In fact, adoption of Windows 8 is even higher than that of Windows 7. “The level of embrace from enthusiasts, from people who want to get out there, is very, very high,” said Ballmer. This figure doesn’t even include sales of new Windows 8 and Windows RT PCs. Customers flocked to Microsoft Stores, in particular, over the weekend in the hopes of picking up a new device like the Surface. On the business side, tens of millions of licenses have been distributed to corporations, although whether or not they will choose to upgrade immediately will be on a case-by-case basis.

With Windows 8 Pro upgrades starting at just $39.99, there’s no reason not to upgrade your old PC. Especially since it will increase performance by 10-40%. Will you be moving to Windows 8?

[Ars Technica]