We have experienced the excact same thing with lag spikes down to 0.3, chat lag, high sim pings (bandwidth going to 0 for seconds), and physics objects flying through the air, for over a month, so you arn't the only one. I haven't checked if it has improved after the restart though as I haven't been much there.
Our estate manager have been unable to do anything about it, all we can watch is the stats go nuts every 2-5 minutes.