I am a Mac user. Which means my daily browser is Safari. This has been the case for a number of years, until version 5.1.4 was released in mid March. Since that time I have experienced excessive memory consumption upwards of 1GB as cost of using Safari. Prior to that release, no noticeable hit to my resources was observed.
I updated my Mac book yesterday and noticed an improvement today. We'll have to see how long that lasts. It's been less than 24 hours, so it really is too early to tell.