Do you have any Safari extensions installed?
Anyway, I'll say this about browsers: Virtually all of them self-update quite frequently. One definite exception is Safari. Updates for Safari come through Software Update and we all know how infrequent those are.
I only try Safari when Firefox won't do something it ought to. So…it goes both ways.
Having said all that…maybe try a different DNS setting. You can have the fastest internet ever but if your DNS is blocking or stalling services you can get clunky behavior.
Also, Apple's own security features sometimes muck up the works. All that "hide me" stuff has to pass through something that might not be playing well with what you're trying to do on the internet.