What kind of cooling do you have on your 2600k?
You would like my havik 140. Those i7s get way hotter than the phenom iis.
i have i7-920 - stock clock is 2.6GHz
--it is at 4.2GHz with a Thermaltake FrioOCK cooler. My article is going up as soon as i get three or four other articles written first. i have also Noctua's flagship NH-DH-14 cooler; i might be able to get another +200MHz out of the old Bloomfield (it is over 2-1/2 years old; the components are barely still in warranty and it *still* keeps up with a mildly overclocked i7-2700K)