See the following sad story:-

http://www.anandtech.com/weblog/showpost.aspx?i=428

Even if you use voltages nowhere as extreme as the Anandtech
reviewers, you may still be contributing to a longer-term
early-failure. These hafnium-gate devices may be a lot less
accommodating of overstress than previous gate technology. It would be
very wise to respect Intel's recommended voltage maximums and let
other 'guinea-pigs' ( or those with lots of spare cash) fill in the
MTBF vs voltage profiles of 45nm processors..

John Lewis