TSMC 40nm is still immature
TSMC's 40nm process maturity can simply be described as disastrously bad. According to our sources, yields are currently at around 50 percent, which is catastrophic for a mature and more than a year old process. One could say that TSMC is really immature about its 40 nm yields.
At this time, TSMC should be at 90 percent + yields, but this is simply not happening. The worst part is that nothing will change in early 2010. The shortage will last throughout Q1 2010 and both ATIs RV870 and Nvidias Fermi will be heavily affected to their die size and complexity.
Things might start getting better in Q2 2010, but this means that you might have to wait all the way to April 2010 if not later to get more than a single 40nm card sitting on the store shelve for more than a day.