How much of the battery life on a tablet is RAM? I moved down from 8GB to 4 when I switched from a big laptop to surface, and the only performance difference I

How much of the battery life on a tablet is RAM? I moved down from 8GB to 4 when I switched from a big laptop to surface, and the only performance difference I noticed was substantially improved hibernate times. I'd hate to get a bunch of battery life back from Haswell just to burn it all on RAM I don't even want to get the 512GB model.