lemmy.world feedback is that 0.17.4 performs better than 0.18.1 - is this true? What is slower?

Specifically the database backend. Is the polling for notifications causing more database load? From my personal testing, lemmy.ml has the same performance problems with 0.17.4 that it does with 0.18.1 and I haven't seen anything in the code changes that are that significant with database.