my ac3 is lagging a little bit my config is 4gb ram ddr3, 2.10ghz max turbo 2.40ghz,xfx ati radeon hd 1gb ddr3, internal 1.75gb graphics , motherboard- asus mlx plus crossfire x ready,OS- win7 ultimate, proscessor- amd a6-3500 apu .with radeon {tm} hd graphics.what should i do please answer me