OS X 10.5 Standard Safari, not the beta, and it keeps freeking out, 100% cpu usage and just locks up. Ran disk utility and repaired everything. Doesn't do it right away, about 3-5 min into using a session. No clue whats up.
I don't think the Safari version that OP is using has that feature. He says he is not using the beta version. I might be wrong about the non-beta version not having it.