Hello, I'm pretty new to overclocking and already understand most aspects of it by reading the posts and google, but what have been confusing me are the FSB and MCH voltages.

Can someone please explain to me how will I know if I need to increase them?

For example, say I overclock an e6400 to 3.2 ghz (400 mhz) with 1.35 vcore, I run some tests (orthos, small ffts) and it fails.

I've run memtest on my memory with the timings I want overnight at 800 mhz and there were no errors.

Now what I know so far is that here is where I up my vcore and try again, until I get it stable without failing orthos.

So my question is :

1) When exactly do I need to up my FSB or MCH voltages? How will I know? Or is it just guess work?

2) Will upping my FSB or MCH allow me to run at a lower vcore ? Or it does not work that way?

3) If yes, FSB/MCH voltage vs. Vcore, which one is the better one to decrease/increase in terms of being safer, more stable, long term usage, etc. (i.e +0.1V on FSB is better than having to increase +0.05V on Vcore, something like that, if it works that way anyway)

Will really appreciate it if someone can answer these questions

Thanks in advance