and I repeat that it happens only in multiplayer, so I think is something server-side, but why some people notice it more thean others?
I experience severe stuttering when artillery lands (still), when reinforcement waves appear and at seemingly random moments throughout. It doesn't appear to be geometry density based because I can view high complexity models with fluidity between these judders and stutters, and it occurs in SP and MP games which would suggest it's not latency related either. Various detail settings have minimal impact on stuttering.
(AMD X4 965, ATi6870, 4GB, W7-64)