Most probably higher Vcore will result more electrical leak which will slowly generate more hot spot and eventually destroy the transistor.

Maybe lower resistence transistor easier to get spoiled?

My first Tbred B is 1700+ UT3C 0302 WPMW, I feed 2v for it to run 100% stable at 2.26GHz, but it was running cooler than my current 1800+ 0310 LT3C VPMW at the same clock speed, 1.65v.

btw my nickname at forum.lowyat.net is Austin.
Although it is a smaller community among our Malaysian OC Enthusiasts, but I hope we can often exchange our idea/info/xprience.

http://forum.lowyat.net/index.php?act=ST&f=5&t=612