Tak uz fakt neviem ze co je pravda a comu mam veritFor 90nm cores (i.e. Sandiego, Venice, x2, Winnies) its best to stick around 1.6v-1.65v MAX
For 130nm cores (i.e. Clawhammer, newcastles) you can go a little higher to 1.7v-1.75v but always make sure temps are good.

