Battery life/loss from ram is a big question,
Newer...well every single upgrade of ram, from sdram all the way to the not yet(?) released ddr4, has featured better power management on-chip as well as needing lower voltages. SDRAM was running at 3.3 volts i believe, and DDR brought this down to about 2.5. DDR2 lowered the voltage to 1.9, and ddr3 can go to 1.5 volts or below. Also, the ram in phones is run at an even lower voltage, being specially made for low power platforms.
Power used is offset by the ram running at higher speeds. You will not see any difference in battery life from the ram, i dont think.
But this is purely speculation. Ask all you want, but we will not truly know until these phones are released into the wild and compared.
Sent from the Blue Falcon cockpit on my Fission 2.4.3 D2G