Premium is Double XP from today at about 7am CST to I believe the end of Sunday night. 58 hours is what they said. Hit 110, trying to get the rest of some minor stuff through weapon battle packs...
If you want the game to launch the x86 version through Origin and Battleblog, on your "My games" tab of Origin, right click BF4 and select "Game Properties". Change "When launching this game" to Battlefield x86.