What is the difference of RM 875 & RM 877 Roms

[Shinku5]

I have RM 875 device. But when I install RM 875 rom my battery drains fastly, when I install RM 877 Argentina rom my battery is so good. What is the difference?

 

[Mr Kaja]

RM-877 phones at least support another 4G sites, so this won't probably work.