Although the launch of AMD's new dual-core Radeon HD 6990 GPU (Antilles) was delayed until the first quarter of 2011, sources from graphics card makers believe the issue is unlikely to cause a great impact on AMD's market share and Nvidia may still have difficulty retrieving the number one position in the market without a product that delivers a good performance/price ratio.

AMD recently postponed its planned Radeon HD 6990 GPU until the first quarter of 2011, though the reason for the delay is unclear, the sources noted. In addition to its dual-core Radeon HD 6990, AMD also plans to launch mid-range Turks and entry-level Caicos GPUs in the first quarter of 2011.

On the other hand, Nvidia is set to launch its GeForce GTX 560 in the first quarter of 2011 with performance to be 15-20% faster than the GeForce GTX 460. Nvidia is also ready to launch its GeForce GT 540 and GT 520 in the first half of 2011.

Both Nvidia and AMD declined to comment on unannounced products.