I had this problem months ago...safari running slowly...
the pages seem to have a delay displaying content... blue line runs through address bar and I get a 3-5 second delay before I see the full web page.
I have done a clean install, I have unplugged my router and ISP modem, repaired permissions, tried 32 bit, 64bit
I have speed tested my MAC Pro and my Macbook Pro.
Macpro gets sporadic results and macbook is very consistent... on the same network.
very frustrated and do not know what to do anymore
my MAC Pro is 2006
ISP has changed my modem, apple says it's interference, yet the macbook works fine,
apple also stated that my macpro cannot operate at the same internet speed as my macbook(2007)
I've since added some RAM, bought it from OWC, noticed that other day that my second display is a times overheating
I've spent a tome of money on this computer and can't understand why I can't surf the web like a hero, also noticing that steaming video is very slow i.e. youtube