Well of course you should be able to play Attila and Rome 2 on high settings, while I still want to point out that Ultra or Extreme presets are not the highest settings possible, so it is rather ashaming that you don't max out Rome 2 for sake of more performance with your powerful build.
TW Attila is not a 64bit engine, this can be firmly excluded regarding the system requirements still allow a 32 bit OS. I hope that TW Warhammer will support only 64bit and still I think it needs a new engine, too because of the unit and battle engine that has higher unit diversity. My hope rely on the information that the Warhammer team is a complete different Team to TW Rome 2 / Attila, so the chance they are also crafting a new engine is very likely.