I think that I'm quite lucky because I tend to look at the board first thing in the morning which is long before America wakes up and turns on all those zillion computers. I usually get through the volume reading very quickly as it switches between pages very quickly. When I use the computer at night (now its nearly 11pm, so 3-7pm USA time) it is much slower.
What I would really prefer is the option to load the pages of the threads in reverse order, so I can look at the most recent posts quickly. I use threaded mode in the first instance (as that shows me where the new posts are), then once I'm in a thread I find it works (for me) fastest to go straight back into flat mode and then "show all" immediately. This means that I can move up and down quickly as the replies do not always relate to the previous post. If I get really lost, I turn back to threaded for a while but I find it slow to load individual messages one at a time. Once I've downloaded all the pages I can turn off my connection and read off line if there are lots of posts.
