i see a lot of talk about oc'ing this cpu, but not about undervolting; which i find strange since this is spcr. i'd like to replace my 1900+ in my fujitsu s2020 with a 2500+, and undervolt it a bit. any idea if this is possible? and how well it would work? good idea? bad idea?

I undervolted my *non*mobile Barton 2500+ from 1.65v stock to 1.35v successfully - it really drops temps and allows for slower spinning/quieter fans.

how doable is it to undervolt on this notebook? any idea? is it more difficult to undervolt on a notebook? is voltage the only thing that is to be considred for heat production? or does cpu speed go into it as well?

you're going to have to explore your bios for those answers.