Recently started playing PA again after getting Titans, and I'm getting massive FPS drops whenever the tier 1 vehicles are fighting on screen. I can have 100s of gunships or bots and keep >60fps, but as soon as I (or the AI) builds tanks (I think it's the Ant) my framerate tanks to 1fps and the audio stutters. CPU usage drops when this happens leading me to believe it's something to do with the graphics. I've tried various things from the different threads on framerate issues to no avail. I have a modest system (i5 4790, GTX 750 Ti, 16GB ram) but this is well above the system requirements and shouldn't be having these issues.