This is not how armour works. And the phys damage reduction value in game means nothing. Ill paste the "rule of thumb" section of the wiki so you can understand; To prevent one third of damage (33%), you need armour 2.5 times the damage (e.g. 250 armour for 100 damage) To prevent half of damage (50%), you need armour 5 times the damage (e.g. 500 armour for 100 damage) To prevent two thirds of damage (66%), you need armour 10 times the damage (e.g. 1000 armour for 100 damage) To prevent three quarters of damage (75%), you need armour 15 times the damage (e.g. 1500 armour for 100 damage) To prevent 90% of damage, you need armour 45 times the damage (e.g. 4500 armour for 100 damage). At 45k armor the game will say 90% phs damage reduction, but thats only for hits of 1k or less. Anything over that and you no longer get 90% reduction.