I've noticed sealed games have started to drag as the games go on. Usually I seem my opponent's clock going down, I'm f-6'd and then the turn changes and I see their clock bounce back up 20 or 30 seconds and then mine goes down a bit. I only am noticing this on sealed games, possibly because of the bigger sideboard, not quite sure. It also doesn't start quite so bad, but I did try to relaunch the client while sideboarding and it didn't seem to help.