The problems affect systems that use the current version of Intel's Atom line, known as Cedar Trail. Intel is rolling out a new version of Atom, called Clover Trail, that is specifically designed for Windows 8 hardware, but that's too late for many users who previously bought systems on the belief they could upgrade later.
They're most likely out of luck unless they can devise a workaround or if Intel, which did not return a request for comment, steps up with a fix.
An example of a Windows 7 system that, on paper, meets Microsoft's minimum requirements for a Windows 8 upgrade, but which, according to its manufacturer, can't be upgraded is the Asus Eee PC 1225C netbook.
With a 1.86-GHz processor, 2 GB of RAM, support for DirectX 9 graphics, and an HD display resolution of 1366 x 768, the system meets or exceeds Microsoft's recommended Windows 8 system requirements.
But there's one problem. The Eee PC 1225C uses the Cedar Trail N2800 processor and its companion graphics component, the Intel Graphics Media Accelerator 3650. Asus indicates on a support site that its tests show the device is not upgradeable to Windows 8, and blames its Intel architecture.
[ Learn more about Microsoft's bold new OS and why Apple should be worried. See Windows 8 Beats The Mac, Appsolutely. ]
"The tested systems cannot be upgraded from Microsoft Windows 7 operation system to Microsoft Windows 8 operation system due to Cedar Trail chipset is not supporting upgrade to Windows 8," Acer states.
Another Windows 7 device, which debuted as recently as July, that can't be upgraded to Windows 8 is the Fujitsu Q552 tablet. The $850 tablet sports Windows 7 Professional, a touchscreen, 2 GB of RAM, and 64 GB of storage. But despite the fact it's only four months old, users can forget upgrading to Windows 8. The reason: its specs include the Clover Trail N2600 processor and 3600 GMA.
"Cedar Trail won't support Windows 8 because of the architecture of the CPU," Paul Moore, VP of product management for Fujitsu America, told InformationWeek, in an interview.
The issue appears to affect dozens of systems from numerous manufacturers in addition to those already mentioned, including HP and its Mini 210 HD, Toshiba's WT200, and the Lenovo IdeaPad S110. Windows 7 tablets that use Intel's Core architecture, like the Samsung Series 7 Slate PC, are not affected.
Many users blame Intel for the problem, claiming the chipmaker is refusing to release the drivers that the Cedar Trail GMA would require to run Windows 8.
"I believe there are thousands of Intel's customers that are going to face this problem in the future once they begin to upgrade their operating systems to the new Windows 8," one frustrated user wrote on an Intel support forum. "Installation fails," complained another. The issue also appears to affect previous generations of Atom, such as Pine Trail, which uses GMA 3150 for graphics. "It's a bit late to be finding out there may be a driver issue," said Gartner analyst Martin Reynolds.
Intel launched the Atom line in 2008, in response to ARM Holdings' growing dominance of the mobile device processor market. Industry watchers say the architecture has been plagued by graphics problems ever since. "The graphics are broken," said Charlie Demerjian, an analyst with the semiconductor industry research firm SemiAccurate. "Atom didn't work well on operating systems that were out previously, so what are the odds it's going to work for a system like Windows 8.
The problem is more than academic. IT buyers are at a crucial point where they need to decide whether to stock up on new Windows 8 devices, which hit the market Friday, or stick with Windows 7 systems. If they opt for Windows 7 devices based on Cedar Trail, they won't have the option to upgrade later, warned Fujitsu's Moore.
Further complicating the issue, according to Moore, is that Windows 8 systems that run Clover Trail won't be capable of running Windows 7. "You have to make a commitment one way or the other," said Moore.
The issue has Fujitsu hedging its bets by rolling out a tablet, the Stylistic Q572, that will use AMD's new Z-60 "Hondo" mobile architecture, which Moore said can run Windows 8 Pro or Windows 7. All Windows 8 tablets that run Windows RT, a variant of Windows 8, use chips based on ARM's mobile reference design. Those systems will not be capable of running apps written for Windows 7 or older versions of Windows.
The bottom line, according to experts: Enterprises or individuals contemplating a tablet purchase should decide which applications are most important to them, and choose a device that will support those apps, regardless of OS.