So resistance reduction = 1/5th effective on resistances over 100

so 115 light resist = 175
145 fire res = 325 fire res
175 cold res = 475 cold res

So if you have a lvl 99 cold mastery skill + infinity, why can't you break the immunity?

Only Conviction/Lower Resist are able to break elemental immunities (as you said, working at 1/5 effectiveness against resistances over 100%). All other sources of - resist (Cold Mastery, RBFs etc) just dont get applied until the resistance is below 100%

This

Fire and cold immunes are usually higher resist than light hence why light is best infinity sorc user

I find this to be really, really stupid though. It makes cold sorc mastery counter-productive.

Shit if it worked at 20% efficiency you'd still struggle to break immunities anyways no?

Why hasn't blizz changed this

Cold mastery is more for pvp than pvm

Everything in this game was made for pvm, not pvp. PvP was a sub-category during d2 development.

The fact it's considered "for pvp" is a testament to how useless it is in pve

seems fair to me cold sorc still one of the better pvm'ers just use reapers toll instead of infinity

This post was edited by B00MAN on Aug 16 2022 01:44am

Why reaper over insight? For the slow I guess? Is it really worth it?

its noticeably better than insight imo decrepify & HF aura is op and cold sorc is not super mana hungry anyway

Because there is a reason for the existence of immunities. It forces you to play around them, and not just brute force every monster to death.
If CM would break it, fire and lightning spells would be insanely bad compared to cold.

CM is really strong for PvM. If a monster has 50 cres and your CM reduces it by 150, you deal 4x your normal cold dmg