id summary reporter owner description type status milestone component version severity resolution keywords cc 9282 performance regression in boost::unordered on 64-bit platforms aiapub-cpp@… Daniel James "On 64-bit platforms boost::unordered containers use 'mix64_policy' which doesn't grow the bucket count as fast as the 'prime' version. That makes adding items to an empty/'non-reserved' container extremely slow. Changing new_bucket_count/prev_bucket_count should fix the problem. Versions affected: 1.50 and above. Regards, - Ildar." Bugs closed Boost 1.56.0 unordered Boost 1.53.0 Regression fixed unordered mix64_policy performance