Here's how impen math is done to my knowledge. Each point of impen is worth 1/66% damage reduction on crits. So lets say you build a toon with 2500 impen which is pretty common in PvP;

2500/66 = 37.8% damage reduction from crits.

Assuming a player with 1.7x crit multiplier attacks you and crits with an ability that has a tooltip of 15k.
For case with no impen;

1) 15k x 1.7 (for crit multiplier) = 25.5k
2) cyro 50% debuff = 12.75k before factoring in penetration or resistances

for case with 2500 impen;

1) 15k x (1.7-.378) (for crit multiplier - impen reduction) = 19.83k
2) cyro 50% debuff = 9.915k before factoring in penetration and resistances.

Total damage mitigated before defences = 12.75 - 9.915 = 2.835 --> that's about 22% flat out damage reduction

Considering things like divines and infused only offer marginal total of 5-10% DPS or stat increase, impen is flat out the best trait in PvP. Unless you are running some one shot QQ 6k weapon damage build that has no intention of ever taking part in sustained battles, it would be wise to run impen for the case of PvP.

Also,

attackjet wrote: »

DannyLV702 wrote: »

Yes it does. If you're not rocking impen then you're going to be eating 20k frags and everything else

I've heard with impenetrable you can make it so crits do less than regular attacks, is this true?

I do not think Impen can ever make crits do less than regular attacks unless someone has no bonus to crit damage at all which is never the case. (ie they only have a base multiplier of 1.5x). You would need more than 50% reduction from impen. Based on the formula above; that means you would need 50*66 impen= 3300 impen to totally mitigate crit damage. Ie: A crit will do the same damage as a normal attack if someone has only the base multiplier of 50% bonus to crits. Considering that there are SO many buffs that increase crit damage, especially for NBs, one would expect to see a typical crit modifier of about 70% extra. So you would need 70*55 impen to negate this = 3850.

To my knowledge, full gold impen gives 2000 impen. 25% from hardy would give another 1650. So the MAX you can get at the moment would be 3650 impen. So it is technically possible to reduce someone's crit to less than base IF and ONLY if they have a multiplier of (3650/66) = 1.55x approx. This is never the case tho. Just the blue CP tree has so much bonus to crit damage. I believe most people would run more than 1.6X multipliers.

Hope this helped!

EDIT: fixed formula.