Hey, I never used to have this problem when I was playing from north america. Recently I moved to South Korea, and since then I have been experiencing extremely high lag when playing around 9pm Korean time, or 8am EST. This has been quite consistant, and its not due to my internet connection. I still download and stream at the same speed/everything else works. It also is just me, since everyone else on the server is playing just fine. The game basically lags to a stop so I have to quit. Upon relogging there is around 5seconds where I do not lag and can move around, but the game quickly becomes unplayable for me again.
The server has problems with lag, if that only happens you then it is not caused by the server. Do you have any antivirus programs set to run at a certain time?
Not that I know of, nothing has changed regarding the software on my computer from when I was back in North America. Last night it lagged in the middle of selling leech, so I had to refund the last half and log off. It usually goes away after a hour or so though. I have no idea what could be causing this.