Yes, logging out and back in has helped me immensely. I'm guessing the RAM just gets clogged, so purging it will get things back to normal. I imagine getting more RAM would also help, but I'm cheap.
I've found the lag is awful in all the city zones. I slowed to a crawl moving through Freeport...1 frame every 10 seconds at a couple points...but as soon as I got out of it, everything was fine. I ran around the Commonlands for hours last night before I got around to purging the RAM, and didn't slow down or skip at all.
My conclusion: the city zones need some work to handle the heavy loads in them. Hopefully SOE has some way of fixing the code (unlike EQ1, when the Bazaar was always a slideshow) or they're going to have a lot of unhappy customers.