How many points does a blizz Sorc need with a sunder charm?
Still up to -100?

really depends on what you are doing and your gear

if you are just doing mephisto he has 75% cold resis i believe, so you will need 170% after sunder

Just farming around a bit in terror zones / dia / baal etc
Not based on bosses or anything

th best case scenario would be to find the average cold resist of the areas you farm and get a cold mastery that reduces that to the max.

but thats not really practical

just max it, its not it reallty matters for a cold sorc anyway you just destroy everything in your path

-150 is my go to, which is pretty easy to obtain when you have facets, Torch, and end game gear. Non immunes still have cold res, so you still can go way up and be effective with it. I've also done Dclone with Sorc, which is doable with higher Cold Mastery due to his high res numbers.

Pretty much you want a total of 28 points into Cold Mastery. Subtract 1 point for every -5 res you can use with from Facets, Gear, or Auras.

This post was edited by eric1014153 on Nov 3 2022 11:15am

I made a test, cold mastery can pierce the res to maximum -100%, not only stop at 0%. Sunder makes immue mons become 95% cold res, so you need total -195% to put them to -100% res.
Your gear may have 3x cold facet (helm/orb/armor), so you already have -15% cold res here
That means you need more -180% cold res in cold mastery. Its cold mastery level 33 (32 without battle command buff)
You can save points in cold mastery by + skill from gears, charms

This post was edited by doantiep on Nov 6 2022 03:39pm