i too get such issue.... played both asia and america server, both got similer issue.

got a latency bar beside the menu button, for my case, full bar is green but most of the time it shows only 2/3 bar, worst at 1/3 bar which is red.

at some moment, it will drop from 2/3 to 1/3, then jump up to 2/3, then drop to 1/3 , then up again..... this might happen from time to time, until it stable again....

still, most of the time I able to play D3 smoothly , just that these lag and delay really is frustrating, specially when hitting those elite mobs in nightmare or hell ....