I bought my new gaming computer 3 months ago, it's a i5-2500k@stock and a gtx 670. I never used to have less than 60 fps's not even when there was big explosion in BF3 I've always played on ultra settings.. But since a few weeks ago, In some moments it goes to 40-45 fps's .. Is it normal that as the pc gets older to see the fps's dropping? It may be normal, but 20fps's looks just too much!
Did you install beta drivers? They may not be working correctly. Is this on the new DLC that just came out? Could be a little harder to run that the rest of the maps. 40-45 fps minimums sounds normal if you have ultra and 4xaa.