It's more complicated than that. Also overclocking can damage your
computer and shorten it's lifespan. If you don't know what you are
doing I strongly advise you to read some articles about it first.
Here are some and you can Google some more:
http://www.anandtech.com/showdoc.aspx?i=2903&p=1
http://www.anandtech.com/showdoc.aspx?i=2802&p=1
BTW, I didn't have to raise my processor voltage in order to overclock
it to 3 GHz.
In a nut shell to overclock you CPU, you have to raise the FSB speed.
You have to have a motherboard and BIOS that lets you do this. Also
when you increase the FSB, you'll overclock your memory also unless
you compensate by dropping your memory ratio. At higer overclocks
you'll need to increse voltages to get your system to be stable.
Doing this is risky. An overclock CPU draws more power especially at
higer voltages, so your power supply better be up to it. Also a CPU
gets hotter when you run it faster. Depending on much you overclock
it you may need a better CPU cooler. Here's a link to graphs showing
the cooling abillities of various coolers:
http://www.anandtech.com/casecooling/showdoc.aspx?i=2943&p=3
Unless you have an understanding about these things, do not overclock.
George
George