Server lag would be, for example, you move a piece and the piece doesn't move for your players until 30 seconds later. This sounds more like a local processing issue (at least, based on what you're saying). Lag when scrolling definitely wouldn't have anything to do with the server. We do some additional processing now when you first load the page if you are using really large graphics (like, larger than 1,500x1,500 pixels). Basically we trade some additional load right when you first load the page so that it renders a lot faster while you're actually using the page. How much lag are we talking about? A second or two? Or a minute? You might provide a link to the campaign so we can investigate further as well.
