Thanks for the Memory (Score 1)

For me, it's the memory issue. I tend to run Safari for days without restarting, and while I cannot confirm that there are memory leaks, I can tell you that it eventually consumes any memory that it can find. Closing all open windows has little or no effect (I did not trying clearing the cache on the odd chance that it might be affecting the situation). If I restart Safari, the memory footprint shrinks back to "normal" (whatever that is), and the entire performance of my system improves.

When I get an overall slowdown, top shows lots of pageouts. I'm guessing the disk hits are what is actually killing much of the performance.

Occasionally, I go to a page that sucks the CPUs dry, but that's the exception. Memory seems more of the culprit...