Last pack of upgrade: v1.6 - I noticed a strange effect using full linked (laser and ion) fire with a Tie Defender: the pirotechnics of the damages make a particular "hiccup" in the frame rate. When I fire only laser or ion, or the target is "big" (a starship or a station or a container) that do not happen.
I tryed several combination of setups and this is the only factor I can give. There is some minor bit somewhere - very minor and little visible, that has to be turned to fix it.