TSMC said it has seen yield rates for its 40nm node drop to 40% due chamber matching issues. Main customers for TSMC's 40nm processes are GPU vendors AMD, which recently launched its new 40nm-based Radeon 5870 series, and Nvidia, who is scheduled to launch its 40nm-based GT300 series of chips in December, according to previous reports. TSMC's recent issues may impact the shipping schedules of the GPU vendors, market watchers commented.