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Quite frankly, the additional two cores of the 1045 aren't really of use when gaming. The higher CPU frequncy of the 965 will be of use.
Personally here, I would get the 965.
Fx 6300 is IMO the best gaming chip from amd it's only $10 more than the 4300 so it's priced nicely and games don't need the 8 cores on the 8320/50. Get the 6300 or if your really need to save money the 4300 is fine too