It's odd. I get the impression that, when you make posts, new topics or edits, it reaches the server almost instantly, as when the page finally loads, it shows someone posting after you within the timeframe that you were waiting for the page to load. Theoretically, if your post didn't reach the server until the page actually loaded, the person after you would be before you, no?
It seems to be more of a page load issue alone than it is the speed of data transfer altogether - you can get to the server quickly, but the server takes time to get to you.