I heard JJ from ASUS on a newegg video on youtube say that you don't want to go beyond 1.350v nor 4.8Ghz on Ivy
EDIT: You might want to watch this vid COMPLETELY before you do anything to you PC.http://www.youtube.com/watch?v=4mkGQhE1o2w
You are so right. Just looking around the net at some of the voltages and temps people are using after seeing this video about 3 times just scares me!!