Framedrop when translating camera

I’m experiencing tremendous amounts of frame drops when translating the camera while displaying 4/500 billboards as seen in the following screenshot.

http://puu.sh/iVQXv/b9548fce77.png

Funnily enough, i’ve already disabled every postprocess effect, and it doesn’t happen when rotating the camera.

Is there any way to prevent this?

Thanks,
Riccardo

Ok, rotating the text mesh seems to be the problem.

I applied a billboard material, now it runs smooth (23ms/frame).