1. An apparatus for branch prediction comprising: a branch history buffer for capturing addresses of non-biased conditional branches provided by an instruction stream and positions of the non-biased conditional branches during execution of the instruction stream; a biased branch filter distinguishing between biased conditional branches and non-biased conditional branches and selectively blocking the distinguished biased conditional branches from being included in the branch history buffer, wherein biased conditional branches are consistently skewed toward one direction during execution of the instruction stream and non-biased conditional branches resolve in either direction during execution of the instruction stream; and a circuit correlating earlier non-biased conditional branches captured in the branch history buffer to pending non-biased conditional branches and not correlating earlier distinguished biased conditional branches that are not captured in the branch history buffer to pending non-biased conditional branches, the circuit comprising: a weight table including a plurality of weights corresponding to weights for only the non-biased conditional branches captured in the branch history buffer; and a global history register accumulating branch directions for only the non-biased conditional branches captured in the branch history buffer during execution of the instruction stream, wherein the circuit makes a prediction for a pending non-biased conditional branch according to weights and branch directions based on the earlier non-biased conditional branches and not on the earlier distinguished biased conditional branches, and further comprising a duplicate branch filter for detecting a second non-biased conditional branch that is a duplicate of a first non-biased conditional branch held in the branch history buffer and causing the first non-biased conditional branch to be evicted from the branch history buffer in favor of the second non-biased conditional branch, wherein the detecting comprises scanning an address array and a position array to find a last occurrence of the second non-biased conditional branch.