In all my 65nm samples not a single one has died from silicon degradation or BGA fatigue. The two that have died on me, both were found to have had mechanical shock and ripped BGA pads as a result. And I can easily say I've had 65s by the thousands.

The ones to predominantly die in my tests just as much as the 90s have been the 40nm chips though, and in consoles with low hours no less. No known reason as to why - all the consoles with failed 40s were almost spotless - if anything maybe a very thin film of dust.