The Inquirer claims ATI wants to reserve the X1900 GTO brand for a next-generation mainstream graphics card based on the RV560/RV570 GPU.
At the same time, the company has decided to release an R580-based Radeon X1900 GT card and we expect to see it in early May, probably the second week of that month.
Sources close to company suggest that ATI doesn’t have a shortage of R580 production, but it claims it doesn’t have enough fall-out chips - those unable to reach the top frequency and have under-powered pipes inside. This is how you usually make the slower variations, as not all the chips will work at the desired 650MHz frequency.
In ATIs case, most of its R580 chips will work at either 650MHz and assume the guise of an XTX card, or will work at 625MHz and become an X1900 XT card.