The gang over at VR-Zone believe they have it on good authority that AMD's upcoming Cayman card, otherwise known as the Radeon HD 6970, is being delayed, but not because of yield issues as some have speculated. Citing an "insider," VR-Zone says the problem has to do with a shortage of a specific piece of hardware from Texas Instruments.
Specifically, TI is having trouble supplying an integrated driver-MOSFET (DrMOS) that was introduced on AMD's HD 6800 series. Because it's such a new part, there isn't much info floating around cyberspace, only that current supply is limited.
Since the same part is used in current 6800 series cards and because the 6800 and 6900 series use the same VRM design, there just aren't enough parts to go around. That's good news for Nvidia, which just stole back the single-GPU performance crown with its GeForce GTX 580 videocard.
There's still a chance AMD will launch Cayman on November 22nd as originally planned, but if it does, supply will likely be limited.