Hey folks. I bought Diamond for a friend so we could play the expansions (we rocked the original campaign awhile back and had no issues). Well the problem we're hitting is that he is getting some funky movement lag issues on multiplayer but not single player. We tried trouble shooting it and what we've deduced so far is that it isn't my server that is lagging (another person was connected without issue), his internet is fine (speed test came back fine), he can run single player without movement lag, but when he posts his own server, with no one connected he still has the glitchy laggy warpy movement. So it seems to definitely be his client and only when playing multiplayer, hosting or otherwise. Anyone have any ideas?

I have seen that behavior before when the computer is using multicore processors. If the computer is using such a processor you can try going into the nwplayer.ini file and changing the Client CPU Affinity setting to force the game to only use a single core. Values:

-2: Disable Affinity (use multiple processors)
-1: Default to 0
0: Use processor 1
1: Use processor 2
2: Use processor 3
...etc

If you're doing multiplayer over LAN, you also need to make sure you are connecting to a server over different Client Port settings (also in nwplayer.ini). Weird things happen when two clients send data to the server on the same port.

I replied to you on bioware's site, but it's basically the same advice as here soooo

Good Luck :)

Many thanks to you both, we'll give it a shot tonight!