Add Nvidia CEO Jen Hsun Huang to the list of people disappointed with the debut of Windows RT.
"We expected to have sold more than we did," he said Tuesday. "I think everybody expected to have sold more than we did."
Huang was speaking to financial analysts on the sidelines of Nvidia's GPU Technology Conference in San Jose, California.
Windows RT is a version of Windows 8 for Arm-based chips like Nvidia's Tegra processors. Traditional versions of Windows are written to run on Intel and compatible chips, but they won't run on Arm processors. With Arm becoming so popular in tablet computers, Microsoft developed Windows RT to match Android.
The operating system's debut has been met with some confusion by consumers because Windows RT tablets won't run Windows software. They are restricted to apps written specifically for the platform and downloaded through the Windows Store.
Sales of the first round of Windows RT devices have been weaker than many expected, as Huang indicated. The operating system is expected to win just a 2 percent market share this year, according to an estimate published last week by IDC.
Despite the slow launch, Microsoft should continue to concentrate on the Arm platform, said Huang.
"They have to find a way to get into that ecosystem because it's so disruptive. I think it's of some importance to Microsoft to continue to invest in RT," he said.
Nvidia has an interest in the success of RT and the Arm platform because of its Tegra chips.
Huang said one thing he's still hoping for is a version of Microsoft's Outlook email client for Windows RT.
"If Outlook were to show up on RT, my life would be complete," he said. "I am one Outlook away from computing nirvana. Outlook god, please..."
He guessed it's probably something Microsoft can do, if it so decided.
"They own the source code and I know there are smart people up there."
Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is email@example.com