Following numerous rumors last month, Taiwan Semiconductor Manufacturing Company (TSMC) has revealed it recently run into issues with its 40nm process technology impacting yields.

TSMC CEO Morris Chang said that the company has seen yield rates for its 40nm node drop to 40% due to "chamber matching issues", during the company's October 2009 investors report. During TSMC's July 2009 investor?s conference, Chang had revealed that yield rates for 40nm processes had improved to 60%.

The 40nm process troubles seem to have an impact in both AMD and Nvidia's 40nm GPU solutions. When AMD's first 40nm GPU RV740 (HD 4770) released in Q2 2009, availability remained poor due to troubled yields reported to be very low at that time. The company released the 40nm Radeon HD 5800 series of graphics cards earlier this month but still, the availability in the U.S. computer hardware e-tailers for the Radeon HD5850 models is limited and their prices tend to be higher ($280-290) than AMD's recommended price ($260) at the time of their official announcement. AMD is also reportedly speeding up the release of Hemlock GPU that will possibly appear as early as next month. A Radeon HD5970 should fall under top products, and rival Nvidia's dual-core Fermi solution.

Nvidia had delayed the release of a 40nm GPU some months ago, with rumors pointing at low yields on the company's chip provider TSMC. Nvidia is scheduled to launch its 40nm-based GT300 series of chips in December, according to various reports. The company is also expected to release a product based on the Fermi architecture - the GF100 - in December.

Officially, both AMD and Nvidia have claimed in the past that their 40nm processes are yielding just fine.

Although TSMC's report does not clarify which products would suffer most from this yield rate, it is possible to impact the shipping schedules of the GPU vendors.

On a positive note, TSMC CEO Morris Chang has vowed to fix all 40nm issues by the end of 2009.