Lag in game (uswest)

[Wyrm]

Battle.net lags. All the time. I've got a cable modem connection and there are still quite a few hours in the day where the game is all but unplayable. The best way to get the least lag is play during non-peak hours, like 3am-11am and sometimes in the middle of the afternoon. If you go on from 4pm-midnight, expect a lot of lag.

Anyways, your problem sounds pretty normal. When you're standing still there's very little interaction going on with the server, but once you start doing things it's often a game of "tag" between the client and the server, which is why you get lag spikes when you start moving around from a prone position.