From the beginning, AMD has faced issues in supply, resulting in shortages for many cards in the line. The company recently spoke about these shortages, revealing their cause and outlining potential solutions. Dave Baumann, Product Manager for the series, spoke about production issues with TSMC, which resulted in a six-week manufacturing delay.
Without specifying the exact cause, Baumann indicated it was related to the increased complexity of 40nm GPUs. This produced lower-than-expected yields, but AMD did not push back their launch dates in response. Coupled with high demand, the company was simply overwhelmed. It is common to see shortages when a highly-hyped device launches. A recent example is the Apple iPhone, which has faced several shortages throughout its history.
The HD 5970 has impressed hardware reviewers and users around the world, easily attaining the title of the fastest card available. If no one can buy it, though, it won't matter -- Nvidia isn't far behind, and will seek to close the gap. Even a shortage lasting only a few weeks could cost AMD greatly.