How big is the difference between beam overload I and II?
Whether FBP 1 shots you on the 1st or 2nd pulse
But if you wanted dmg numbers, it's base on the weapon dmg, and then a modifier applied to it. So numbers posted above, would be for RA/BG 5. (Mk X) with consoles, etc to boost it, and assuming you fired that w/ full weapon power.