Some seemingly good information from the looks of things:
http://www.neoseeker.com/news/14494...d-frostbite-2-engine-good-news-for-pc-gamers/
Firstly, we learn via Twitter from DICE rendering architect Johann Andersson the engine BF3 is built on -- Frostbite 2.0 -- is "primarily developed for DirectX 11"; XP and DX9 won't be supported (though you may be able to hack it). Also the engine will be especially optmized for 64-bit -- thankfully a lot of you have chosen the road less travelled. Good news in itself, but since consoles only support DX9, the implication is the PC version will be a "true" PC game.
http://www.neoseeker.com/news/14494...d-frostbite-2-engine-good-news-for-pc-gamers/