AMD’s shares are tanking as the company lowered its Q3 2011 revenue and gross margin guidance and mentioned some production related issues.

It is not clear why AMD is doing so badly. Last week AMD introduced its next generation 28nm GPU at Fusion 2011. Technology wise it should have been an ace card but shareholders were not impressed.

Additionally several sites revealed details around AMD’s 8-core processors based on Bulldozer architecture. But again the new developments did not have much impact on the stock. Analyst outfit Sanford C Bernstein Research yawned and downgraded the stock to market perform.

Forbes thinks that the medium to long term view of AMD is solid but the outfit has to get over its supply problems first. While shareholders don't believe in the new technology, it is fairly obvious that Fusion APUs should help gain market share. Bulldozer is promising introduction and AMD is likely to grab some share of server market from its rival Intel, Forbes said.

What might be troubling investors is the fact that Nvidia might come back from the dead and push itself into the mobile market and AMD does not have a cunning plan to stop it.