Bitttymacod (atys)
Since both the particle effects for spells and the sound for same are clientside based as far as I can tell, it is probably something in your system that is interfering. Even other people's animations are client based, though there is a download trigger to tell your client to invoke the effect. (Particle effects for things like fog involve downloaded triggers so there is an effect on bandwidth there. Ditto for mass battles where the server has to update the actions of many many players and NPCs.)
I found, for instance, that I couldn't get good sound if I was running a streaming radio station or any other use of my sound codecs. (Streaming radio had two effects, one related to bandwidth and one to resource usage but even local music interfered.)
Ryzom is a memory and cpu hog, pure and simple. The single biggest thing you can do to improve performance is have at *least* 2GB of memory. By default it assigns itself to Core 1 (or core 0 if you count that way). If you have a dual core processor you can make things much better (especially for dual clients) by assigning one to each. If you have some other application that also works "badly" (i.e. forces itself into core 1) that will cause a problem, but most modern programs are better behaved than that.
for the very reason that windows was a resource hog, i moved to a linux OS, and now i only use (with several memory intensive programs running at once) at most 1.9 GB of a total of 8 GB memory...i also have a dual core CPU, and i have a decent video card...so this is really frustrating...now, i dont run anything but ryzom when i log on to the server, so its not a matter of cpu or memory conflict, i really do think it is an issue of too many effects or sounds being called at one time, and im sure some fat being trimmed would not be a bad thing...it only happens during spells, other particle effects dont have the same problem, and there are many particle effects running all around even just on Silan...its only the spells cast by my PC, or spells cast by enemies that casue this burst of resource hogging...it eventually dies down again, but it can completely render movement impossible if several spell capable mobs attack at one time...this has caused me to die on a number of occaisions because i could not move at all...