
Without the additional content you would still be able to obtain a maximum DR of 91% with power armor. Combined with the five permanent perks (34%) gives the maximum DR without drugs or having less than 20 percent of your hitpoints.

The T-51b power armor and the Enclave Hellfire power armor plus their respective helmets have a max DR of 60. This makes the effects of Nerd Rage and Med-X somewhat questionable, as even without chems, the Lone Wanderer can permanently gain up to 94% Damage Resistance through equipment and perks (with The Pitt additional content). The maximum Damage Resistance is 85%, regardless whether this value is obtained by armor, perks, drugs or a combination of these.


Note, however, the difference from Armor Class, which helps dodge the attack, and Damage Threshold, which reduces damage before the damage resistance.
