after the last game update I had huge fps dumps, a red dot in the server lag section, or even a red x, especially while fighting in an instance.
My character could move but the surroundings seemed frozen and she could not perform any action at all.
Then I searched for the issue on the internet and found an old thread on swtor under server lags and what not, which I unfortunately can't find anymore.
But it was recommended there that you should delete a Cache file. (Open your swtor directory, find swtor, open it and delete DiskcacheArena. This file runs with ram and will be rebuild
automatically after deleting.)
I remembered then, that there's been a similar issue in Everquest 2, where you had to delete that cache too from time to time.
Mine was clattered with over 1gb of stuff I don't know anything of, (in Everquest they claimed there is data in there that you generate while zoning etc...)but since then my game runs as good as