Try going to the options and setting the graphics presets to HIGH then ONLY turning off shadows and unchecking bloom. It worked for me and my computer isn't exactly top of the line.
I thought for a second that it worked (Had four full bars for a second) but it only made it worse :T
Edit- Its not laggy in a jumpy, choppy movements way... but its like, delayed actions. You know? Hit a skill, wait a second or two, action happens.