Santa Clara, Calif.-based Nvidia has released a processor for DirectX 10, the GeForce 8800. The drivers for the GeForce 8800, however, remain in beta and are not WHQL-certified.

Some users are so disgruntled that they have created a Web site threatening a lawsuit.

"Our [quality assurance staffers] didn't expect there to be an extraordinary number of bugs, but people are hammering pretty hard on Vista, and there are obviously some parts that we missed," said Daniel Vivoli, senior vice president for marketing at Nvidia.

While pointing out that other vendors such as mouse and keyboard maker Logitech International SA, sound card maker Creative Technology Ltd. and Cisco Systems Inc., as well as its wireless print server subsidary, Cisco-Linksys LLC, have also gotten complaints for malfunctioning Vista drivers, Vivoli acknowledged that Nvidia deserves the criticism it is receiving.

"Early adopters of Vista are the PC enthusiasts, and that's where we have 90% market share, so it's not surprising we get more heat than ATI," he said.