which is better: voltages on auto or manual?

am thinking about overclocking my Q6600 soon but wanted to know before i start whether i should manually set voltages for everything so that they dont creep up as i overclock.
am not thinking about a huge increase, probably just to about 3GHz so it will be able to run crysis.
im guessing manual is better as it lets you use lower voltages so keeps temps down, right?

I had my voltages on auto for months and when I finally got round to fiddling with it, I found the vcore could be lowered by 0.1 and still be stable.

Helped temps a bit too.

Chimp

Trying to fine tune voltages is a time-consuming task :) If you'd like a quick and easy overclock then leaving voltages on auto is the best way to go. You know your chip can handle 3Ghz so just bring down the multiplier and bump up the fsb to reach 3 - 3.2Ghz. As long as you keep an eye on temperatures, leaving voltages on auto should be no problem.