I'm interested in underclocking my droid during the time I'm not used it. The rooting is easy but I'm reading that you need a special rom and kernel to do the overclocking is that the same for underclocking? Do I need a special kernel and rom or can I just root then download the setcpu. And do I need to do a nandroid backup if I'm not doing any rom switching?
Thanks for the help
Some of the roms come with kernels with multiple clock speeds. for example, the one I'm using lets me clock as low as 250 and as high as 1100 with 3 speeds inbetween.
SetCPU, for a dollar in the market, lets you set one profile for charging, one for standby, one for in use, etc. So..while in use my phone is set for 400/1100, and while in standby it is set for 250/400. If someone uses their phone all day then the battery will go down faster than stock. If you have it on standby a lot your battery can last longer than stock.
The only reason for a nandroid backup is to get back to "something" if you mess something up. You can always go back to a stock phone, and start over from scratch.
Read the rom instruction guides for features. For example, link 2 in my signature outlines everything in Adamz rom, including clock speeds.
edit: a stock phone is set up for 250/550 for clock speeds.