With Windows 8.1 as a guide, Microsoft should have no trouble matching that cadence with Windows 10. In other words, if Microsoft launched Windows 10 in October, it should be able to get nearly two-thirds of all Windows 8 and 8.1 PCs (as of that month) onto the new OS by the end of the one-year upgrade span.
Computerworld's forecast does not explicitly take new machines into account — most research firms predict that shipments will stabilize at or slightly under 300 million for the next several years — but only OS adoption. In many if not most cases, a new OS is acquired on a new PC; those, of course, are part of the uptake metric measured by Net Applications.
Figuring Windows 7's migration is trickier. Researcher IDC says that approximately 55% of all PCs are in the hands of consumers, 45% in commercial organizations. If that ratio applies to Windows 7 — which accounted for 61% of all Windows PCs last month — that means consumers' systems represented about 34% of all Windows 7-powered machines.
Commercial PCs would be discarded from the projections: Businesses don't upgrade at the same pace as consumers. Even though they will have to eventually upgrade to Windows 10 — the enterprise standard, Windows 7, exits support in January 2020 — they probably won't begin seriously upgrading until 2018, with the early birds jumping on it in 2016, according to Gartner. So business PCs are off the table.
It would be foolish to assume Windows 7 PCs, even those owned by consumers, would upgrade to Windows 10 at the same rate as those running Windows 8/8.1. Windows 7 runs on more than four times as many systems as do the newer OSes, and moving that massive number will be difficult. But even a "discounted" percentage that does upgrade within the first year would be an enormous pool of machines.
If, say, consumer Windows 7 PCs were upgraded to Windows 10 at just half the rate of Windows 8/8.1, and the upgrades begin in October when Windows 7 should account for 67.5% of all Windows systems, 12.1% of all Windows machines would migrate to the new operating system within 12 months (67.5% X 55% for consumers' part of the total X 32.5% upgrade rate, or half the 65% of Windows 8.1 in a year).
Combine that with the 11.5% from Windows 8/8.1 — by October 2015, the OSes' share should have climbed to just under 17.7% of all Windows machines — and Windows 10 would be on a total of 23.6% of all Windows PCs.
That would be an upgrade speed record for Microsoft, beating even the 20.1% uptake of Windows 7 in its first 12 months.
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