Here is the interesting update on upcoming games to be developed on Frostbite Engine including Battlefield 4 or Battlefield 2143. Johan Andersson, Rendering Architect at DICE working on Frostbite and future DICE/EA games, tweeted:

We'll have Frostbite-powered games in 2013 that will _require_ a 64-bit OS. If you are on 32-bit, great opportunity to upgrade to Windows 8

Whilst I doubt DICE is all too interested in fighting viruses with the NX-bit of an x64 system, with increasing texture sizes and level complexities, I can understand DICE's wish to address more memory, especially for its historically demanding Battlefield game series. 64-bit will also allow the team to reduce its codebase and engine complexity with the knowledge that it won't have to support 32-bit instructions or variables, as, even current-gen consoles are also natively 64-bit.