Irfidel (atys)
I would doubt a connection issue here. Like Grimoire and Bitty I have similar, but slightly different issues: The lags usually do not hit me during battles (just returned from the Marauder Boss hunt and did not have any lags whatsoever, with about 35 homins casting spells). But I do have serious lag issues when walking or running through the streets of Pyr. Sometimes I get a fifth of a second movement, then Ryzom halts for 2 seconds or longer, then another very brief movement. This is a nightmare to work with and stopped me from doing more than the occasional visit to the Ceriakos gate and the trainers right behind it.
I had similar issues in Yrkanis when getting near the street lights there. But this has improved a lot recently. The problems in Pyr appeared maybe about six months ago on my desktop machine, but not on my laptop. Both machines were running fine before. And when I do have the problems in Pyr, the wife can still run through the town without issues - and she's on the same internet connection.
so it seems that this problem is indeed particle related, and perhaps different operating systems are in different stages of update concerning the cleaning of particle systems to optimal performance...in your case it seems that group particles are running fine, and stationary effects are giving you problems, and on mine, it is the opposite...stationary particle systems that run all the time are handled correctly by the game and system, and the individual spell effects are not handled very well...
i would really be interested in finding out what is going on, or if there is indeed work being done to the particle systems in question at this time...they may be releasing incremental updates and this is why not everything is working as well as it should...