This is an issue that has been going on for some time, and requires a major change before it can be resolved.
Each time you use the Logout button and log back in again without closing the main game client (also known as the Flash client*), an increasing amount of RAM is consumed and does not get freed up anymore.
Logging out and in with the same account approximately 10 times can result in a persistent freeze of the game client ("program not responding"), at which point you have to force it to stop.
We are working on a 64-bit version of the client, which should resolve this issue.
*The Flash client is a legacy from the very early years of development, when we were exploring the possibility of having the entire game be browser-based. This idea was eventually dropped entirely in favor of a desktop application, but the core of the game client remained the same.
Nov. 18th - Known issue affecting RAM
