i just find aparticle tool and i find that 1 particle effect is doing massive fps drop, other effects dont rly change much.
and this particle effect is the root problem for the ,fire lag' on multiplayer servers i think, but maybe i am wrong cos in sp or custom mission when alone i dont have ,fire lag', only when i use this particle tool.
tool can be find here
http://www.armaholic.com/page.php?id=21217
ingame load up this particle effect. to produce buggy/massive fps drop
particle name:
A3/data_f/kraker