I just did a benchmark for Battlefield Bad Company 2, for directx 9, directx 11, and for 3 cores and 4 cores. Results showed that directx 11 has a higher lower minimum fps than directx 9 but directx 9 has a higher average FPS. Another thing is that 4 cores compared to 3 cores brings more FPS, both for directx 9, and 11. This was for single player campaign mode Cold War mission, but i don't know whether in actual multiplayer whether 4 cores will show much more improvement over 3 cores regarding FPS.
I can't really do a benchmark for multiplayer, because the gameplay differs substantially, but i'm thinking that there won't be much difference in multiplayer because there are no AI bots, or at least less things for the CPU to process, so minimum and average FPS should be very similar between Phenom ii 720 with 3 cores and phenom ii 720 with 4th core unlocked. Would anybody agree or differ with me? I mean for example i remember comparing Frontlines Fuel of War single player to multiplayer mode, and i saw that single player with the AI bots performed quite a bit slower with FPS going down into high 30s than multiplayer where FPS was always at least in the high 40s and above.
Oh and for Bad company 2 i enabled 4 AA for both directx 9, 11 (forced aa in catalyst control center for directx 9 mode), and i replayed a particular part of the cold war mission with a large amount of AI bots, to make sure that each test was following fixed variables.
The reason for me investigating this is partially because i want to use my pii 720 as a 3 core because i can't monitor the temperatures with the 4th core unlocked.