This is a tradeoff between goodies and speed.
WWWThreads runs dynamcially. Everything you see on the screen is retrieved from the database. This is where the bottleneck at. On the other hand, DCForum use flat base file, and all the files is in static HTML file. And that's the reason DCForum can substain higher load. But modification and addon to DCForum is a pain. Since WWWThreads run dynamically, it can give you real time "bell and whistles", this is something DCForum can not do. However, Since DCForum use static HTML page, its response time is no doubt a lot faster.
One thing WWWThreads can do is to cache the content to .html to speed up the process. But I guess this feature won't be available until Scream work on the template engine that support caching...
Scream, if you have time, you can take a look at this..
http://www.phpinsider.com/php/code/Smarty/docs/
