The lag is always a time-out issue. I can't recall the message exactly, but it's along the lines of 'connection to the server is lost, restart in 10 seconds'.
I can attempt a restart, or refresh the map without anything happening, or with things happening verrrry slowly. To get around it in 24hr games (where I have an hour to take my turn) I simply refresh my page. Sometimes this also takes an age. I cannot really play speed games, because I 'time out' too often.
The event occurs more than once EVERY time I have taken a move in the last 4-5 days.
I'm running IE, just like 80% of the population did 5 years ago. I know their market share is now more like 15%, and there are better options out there, but it's the browser on my company-provided laptop.
I don't usually have much else running when I'm playing. I play after work (as opposed to instead of working:) ) and I may have my Outlook Explorer email open, but that's about all.
EDIT: Just returning to the Forum menu after posting this took almost a minute. I don't have this lag at any other site I visit.
Does this help?