The new graphics cards, the GeForce GTX 480 and GTX 470, are based on Nvidia's new graphics-processing-unit architecture called Fermi, which was announced in September. The GTX 480 has 480 processing cores on one GPU, while the GTX 470 has 448 cores.

The GTX 480 could be the fastest graphics card in the market, and it outperforms rival Advanced Micro Devices' fastest ATI Radeon HD 5870 cards, said Kelt Reeves, president of enthusiast PC maker Falcon Northwest. The card hits new highs of GPU performance, especially in installations where multiple graphics cards are used in systems.

In Falcon Northwest's benchmarks for the game Crysis, one GTX 480 displayed high-definition images at 30 frames per second on a 24-inch monitor, and two GTX 480s displayed at 58 frames per second. By contrast, a single ATI Radeon HD 5870 in the same tests yielded 31 frames per second, and two 5870s scored 44 frames per second.

But the speed benefits are accompanied by high levels of heat generated by the card, which can make systems very noisy, Reeves said. As more heat is generated, the card's cooling fans need to ratchet up, which generates more noise, Reeves said.

"Nvidia has hit a power and thermal threshold that we've been warning them they were heading towards for years," Reeves said.