Minimum And Maximum Processor State "Optimal" Setting

I have Windows Vista Home Premium 32 bit and an AMD X2 Dual-Core QL-60 processor (1.9 GHz).

In Vista Power options, there are 2 settings under Processor Power Management: Minimum and Maximum Processor State.

What are the optimal settings for these options? I fully understand that one might choose to have a lower maximum state when running on battery power to prolong battery life. I can think of no reason to have the maximum state below 100% when running plugged-in (unless, of course, one is trying to save electricity, keep the laptop cooler...)

How does minimum state work and what is the optimal setting? I know the default is 5% (but I've done a lot of Googling and cannot find an educated reason why 5% is the default.) Would it be correct for me to presume that if I set it at (say) 5%, then the processor will never operate below 5% of its capability (or whatever # of MHz is closest to 5% capacity) and will run all the way to the maximum specified state where needed? In other words, am I simply giving the processor the leverage to pick whatever power is required between its minimum and maximum specified states?

If my above assumption is correct and the processor will pick the optimum speed within the min/max range, why would I ever increase the minimum above 5% - and better still, why wouldn't I go right down to 1%? (Having said that, I read in one post that processors don't run in relative percentages - but 500Mhz, 800Mhz or whatever - so if my processor can only go as low as (say) 600MHz and my max is 1,900, then I guess if I set my minimum anywhere between 1 and 32%, it would never go below 600Mhz...)