so i recently built a new system with 2 ATI hd 4890. For the most part these cards run great. However at times i will go from my normal frame rate.(80-140fps on this game) to an intolerable 10-20 fps for a few secs. its rather annoying. had a friend tell me the problem could lie in the game writing and crossfire not working well together. could this be the case and does anyone know of any solutions?