Another week, another major PC vendor announcing that it's planning a Chromebook offering of its own. Previously it was Lenovo; this week, according to reports, it's HP.

Acer, meanwhile, is riding high on its own Chromebook sales, and Samsung's offering is currently the top-selling laptop on Amazon.

As Windows 8 continues to lag, it's difficult not to envision rising anxiety levels at Microsoft in Redmond.

14-inch display

According to a PDF that the Verge found on HP's site (since removed), the company is planning what's referred to as a Pavilion Chromebook.

Featuring a 1.1GHz Celeron processor, 2GB of RAM, and a 16GB solid-state drive, the device will also sport a 14-inch, 1366-by-768 display, the publication reports - considerably bigger than the 11.6-inch screens offered by most of its competitors, though apparently on par in terms of resolution.

Battery life is apparently another key differentiator, however, with the spec sheet listing just 4 hours and 15 minutes. Samsung's Chromebook, by contrast, offers closer to seven hours.

'Another nail in Microsoft's coffin'

Still, it's difficult not to marvel over the growing Chromebook phenomenon, particularly now that such major vendors are getting involved.

Acer President Jim Wong told Bloomberg that Chromebooks have accounted for 5-10% of Acer's US shipments since November.

The Street, meanwhile, recently referred to Lenovo's Chromebook as "another nail in Microsoft's coffin." The success of Samsung's entry, of course, speaks for itself.

No love lost

Microsoft CEO Steve Ballmer will always be famous for calling Linux a "cancer."

And it wasn't all that long ago that he expressed more concern over competition from Linux than from Apple. Soon afterwards, he also didn't hold back in expressing his views of Google's Linux-based Chrome OS.

With four key PC makers now jumping on the Chromebook bandwagon, is Microsoft in a fresh batch of trouble?