ToME: the Tales of Maj'Eyal

Yesterday I ran into a tag-team pair of bosses with 128% resist all. One of them had 100% physical resist.

Am I correct in thinking that:

1. The 100% resist physical is irrelevant given the 128% resist all.
2. You need at least 22% resistance penetration to get any damage through its resistances.

No, on 2. Any resist penetration will get through. (I was labouring under the same assumption about one of the uniques that has 500% resist all and was corrected).

Resistance penetration is multiplicative. Meaning if you had 50% penetration and they have 128% resist, their resist would be reduced to 64%. 100% penetration will totally ignore their resist, regardless of how high it is.

Anyone want to break the tie between Effigy's and Nevuk's responses? Does it take 1% or 22% resistance penetration to start getting damage through 128% Resist All? (...or some other value?)

Resistance penetration is multiplicative, but the resistance gets capped at 100% before penetration is applied. Any amount of resistance penetration will get some damage through 500000% resist all.

An easy way to think about resistance penetration is this: if you have 22% resistance penetration, then 22% of your damage ignores positive resistances.