well, first tell us what it is. SHould be located somewhere in your bios, Vcore, or just CPU Core with a number next to it..check PChealth/status or something similar (im an AMD/Apple guy)
dont mess with Vcore just yet. Thats where you step into irreparable damange Im not sure how you do it on intel chips, i know in some instances soldering and pin closing is involved
Again, im not an intel guy. So thats alien territory for me. What i suggest is posting in CPUs-Intel with what model it is, and seeing what can you get out of it...or go to
www.overclockers.com where i beleive we have a database of CPUs and how far they can be pushed.
research your motherboaord, about HOW do you open it/unlock it (if necesery) about the bios, etc..
youll need to know what kind of bios...Award, Phoenix, etc...itll say at the top of the screen when your in it
And a jump from 3.0 to a straight 3.4 isnt good. Most guys on here swear by "burn in". Generally when OCing, you want to step the CPU in increments of about 50mhz, and run it a LONG time. Abuse it with Prime95. But thats debatable, some guys say it doesnt matter, others do.
I heard one guy slowly got his from 1.8ghz all the way to 3.2ghz, only that was over a few months of small increments...and it was watercooled i think
Once you find your general aread (within 50MHZ) you tweak it by about 5mhz up and down to find your correct spot.