I'm with grinder_gary,
I posted a similar screen shot in another thread, but maybe it will get some traction here. Many times while going from one thread to another or browsing through CNCzone, the page hangs while "Waiting for ads.cnczone.com...". As you can see with the attached screen capture, I waited for at least 78.000s before returning to the previous screen and re-clicking through.
Maybe someone can track down the missing or offending ad or script.
Thanks Paul, the Moderators and everyone else that makes CNCzone such a great forum,