As they stated, Vault size is based on RAM. This also applies to our start menus when in a battle. Having 512mb of RAM makes it nearly impossible for our consoles to render the battle and load the resource heavy menu screen where we can change gear or load a synth. Had they used a simpler system much of this wouldn't be an issue. I believe this game was designed for the new gen consoles and then made backwards compatible without seeing how it actually played. We're all paying for their mistakes right now.