Even when you upgrade your going to want to keep an eye on Safari. I noticed Safari using nearly 4 of my 8gb of ram the other day. I was doing some research and some other people have come to the same conclusion that flash was the culprit. A couple of workarounds were explained, with the easiest being to remove flash on Safari, enjoy the performance boost (everything runs faster), but when you need a video, jump into Google Chrome (which doesn't use the same Flash plugin as OSx) via the Safari developer menu.
1) enable the menu in Safari's prefrences
2) the first drop down option "Open page with: " and select Chrome
Chrome will immediately start and open to the page you want, when you done, simply quit Chrome and that will ensure all the Flash processes have closed in the background