I believe there to be some issue related to damage over time effects, in relation to garbage collection or something similar. Consistently, when in combat my framerate will become worse and worse the longer the game has run, eventually getting to where hitting an enemy freezes the game for several seconds.
In my experience, this occurs regardless of zone- monolith, arena, world areas, etc. and once its begun, the only way to remedy it is to relaunch the game. I’ve attempted to respec passives, remove gear, etc. and it seems to have no noticeable effect on improving performance after it has degraded.
It goes something like:
- Open game
- 160-ish fps out of combat, ~80 fps in combat
- do ~130 arena waves. This number of waves seems to be reasonably consistent (+/- 10 waves) as to when performance issues become significant after relaunching the game.
- ~80 fps out of combat, <1 fps in combat as the game freezes repeatedly until enemies are dead.