The problem in the chipset was traced back to a transistor in the 3Gbps PLL clocking tree. The aforementioned transistor has a very thin gate oxide, which allows you to turn it on with a very low voltage. Unfortunately in this case Intel biased the transistor with too high of a voltage, resulting in higher than expected leakage current. Depending on the physical characteristics of the transistor the leakage current here can increase over time which can ultimately result in this failure on the 3Gbps ports.
While initial reports had suggested that the issue is limited to desktop versions of the platform, Cougar Point is in fact used in both desktop and mobile chipsets based on Sandy Bridge, indicating that the recall could also delay availability of refreshed Apple notebooks such as MacBook Pros.
