Re: Best battery performance ROM ?
It depends on how you define poor.
There's the usual things to do, you can undervolt to help, throttle the top end, get better battery stats to check for wake locks, make sure gps /wifi /bluetooth /sync aren't on when you don't need them. Turn down screen brightness as that probably the biggest drain on battery, so using apps with light background isn't great.
You can use different governor / scheduler combo. Some people say pegasusq /sio is a good one. Some apps help either by turning off services you don't need while your not using your phone or by adding tweaks to help efficiency.
Use search for battery tips as there's a lot of information out there.
That said there's always the old gem of 'new battery' depending on how old her note is. Remember there are larger than 2500mAh batteries out there, although above a certain point the battery gets thick and comes with a new back to help contain it.
Hope that helps.
Sent from my GT-N7000 using xda premium