Since my upgrade to Leopard on one system, I’ve had Safari 3 responding very sluggishly. It sometimes refuses to load pages in a tab, even after more than 15 minutes. Other times, it will load pages, but will just take much longer than it does in another copy of Safari 3 on a different computer, or Firefox on the same computer. The pages may load — more quickly or at all — if I stop the current operation and press Enter in the URL field of the toolbar.
So far, I’ve already tried clearing the cookies from some sites that don’t load, clearing the browser cache in ~/Library/Caches/Safari, and changing DNS temporarily to OpenDNS (based on a tip from the Apple Discussions site that DNS might be at fault). None of these has made much of a difference — although the snappiness imparted by OpenDNS should never be discounted.
Many of the sites or pages that won’t load quickly for me are encrypted with SSL/TLS. Many are shopping sites, which may just be unresponsive themselves during the holiday rush. So my problem could be at any number of levels.
I’m at something of a loss about what else to try, although I can generically try to isolate the problem to a user account and that sort of thing.