What are the performance impications of utf8_bin vs utf8_general_ci collations in mysql?

I am working on a database, where the collation for all text fields seems to be utf8_general_ci. There 开发者_开发技巧are cases where primary and foreign keys are collated utf8_general_ci (such as a session_id ). Does it degrade performance to use a case-insenstive collation on columns where binary comparisons are fine?

Yes, of course it's going to be slower to do more work. Whether the difference is significant to your application is another question.