ATI, a subsidiary of Advanced Micro Devices Inc. that is the second-largest maker of stand-alone graphics card chips, claims that its Catalyst line of drivers is enabling almost all of its game-playing customers to use Vista problem-free or with miniscule drops in performance from what they were getting on Windows XP.

"We're seeing less than a 5 percent gap on average," Ben BarHaim, vice president of ATI's software engineering division, said in an interview last week. He added that ATI has been working "very closely" with Microsoft on Vista over the past four years and that all of the company's drivers are now certified by Microsoft's Windows Hardware Quality Labs (WHQL) operation.

Even before Vista's general release on Jan. 30, gamers using beta versions of the new operating system had reported problems in importing games written for Windows XP and its DirectX 9 graphics engine. The problems primarily involved slow animation performance in graphically-intense, first-person shooter games such as CounterStrike, Half-Life 2, Doom 3 and F.E.A.R., as well as occasional system crashes.

Vista is backward compatible with DirectX 9, for which virtually all PC games available today were written. It also introduces a new graphics engine, called DirectX 10, that eventually should allow games to run faster and display more textured, lifelike images than DirectX 9 supports, according to Microsoft. But a mere handful of games have been written specifically for Vista and DirectX 10 thus far.

Nvidia has beaten ATI to market with the first processor that is compatible with DirectX 10, its GeForce 8800 chip. But Nvidia also appears to have gotten more complaints than ATI has about hiccuping or malfunctioning drivers for its older processors.