There's really nothing to upgrade on that platform, a bulldozer chip won't do any better than a 955. No, AMD and Intel based motherboards/CPUs are not compatible with each other, so the only way to upgrade would be to buy a new motherboard and CPU. A 2500k won't be that big of an upgrade though. Are you getting fps dips on BF3 on maxed out ultra settings, or fps dips on a game like starcraft 2? Also, what's your resolution?