Alaysts at Garnter see no help for the PC biz from the release of Microsoft's new Windows 10 OS, at least for the remaining period within 2015. "The release of Windows 10 on 29 July will contribute to a slowing professional demand for mobile PCs and premium ultra-mobiles in 2015, as lifetimes extend by three months," said Gartner analyst Ranjit Atwal in a statement Tuesday. "However, as suppliers and buyers adjust to new prices, Windows 10 could boost replacements during 2016."

Gartner believes that Windows 10 will result in delayed replacement PC purchases as enterprises and other large organizations put plans on hold as they begin evaluating the OS.

According to Atwal, Windows will power about 323 million devices shipped in 2015, a 1.5 percent year-over-year decline.