Sources close to ATI, graphics product group of Advanced Micro Devices, said that graphics cards with 1GB of memory based on the company’s latest high end graphics processing unit (GPU) are an initiative of certain add-in-board (AIB) suppliers, but not the chip designer itself.

The possible introduction of ATI Radeon HD 2900 XT graphics cards with 1GB of GDDR4 memory onboard has been discussed for several weeks with some even referring to it as to ATI Radeon HD 2900 XTX product, which AMD kept in its pocket to launch at a time it needs to compete against its rival Nvidia Corp. with something more advanced than currently shipping Radeon HD 2900 XT 512MB.

However, Advanced Micro Devices has decided not to officially unveil higher-speed graphics card with 1GB of memory, possibly due to the lack of interest in picking up GPUs capable of operating at clock-speed higher than 742MHz, a costly task that may still not allow the company to capture a significant market share.

It is unclear whether AMD plans to introduce ATI Radeon HD 2900 XL or Pro versions based on graphics processors with disabled execution units or with lowered clock-speeds.

The company still allows its partners to supply pre-overclocked high-end graphics cards. As a result, a number of ATI’s partners, among which is Diamond Multimedia, decided to offer Radeon HD 2900 graphics cards with 1GB of GDDR4 memory, which are going to be faster than currently shipping 512MB GDDR3 version. Clock-speeds of the parts are likely to vary, as those graphics cards are made at special requests of AIB companies.

The new ATI Radeon HD 2900 XT with 1GB of GDDR4 memory onboard can be pre-ordered from an online store for about $610 (649 CAD). Earlier it was reported that Radeon HD 2900 XTX 1GB had its chip clocked at 742MHz, whereas GDDR4 operated at 2050MHz. But according to specs published by the Internet store, the novelty has 825MHz chip and 2100MHz memory.

Officials for AMD did not comment on the news-story.