Best to start from scratch and approach the overclocking process properly. Diving head
first into it with core voltage increases is not the best approach. Instead, do it step by
step and you'll not only achieve better results, you'll learn a lot along the way. See:
First thing I would recommend, as the article says, is to ensure your heat sink is
attached in the correct manner as per the instructions from Arctic Silver:
Download the PDF relevant to your system and read through the instructions
carefully. Before, using my own 'normal' method (thin paste layer over the whole
chip surface), I had uneven core temps. Thus, I redid the HS attachment using AS'
instructions; temps were not only much more even, they were also a couple of
degrees lower overall. Well worth doing.
I now have my 860 running at 4011 (191 x 21):