Infinity gives -17% vs immunes
Sunder sets res to 95%, no matter high high it was (it can be above 100)
If a monster has 117+ res, infinity wont break it, you need the sunder.
Even if a monster has flush 100% res, the sunder is still at minimum an extra 5% pen.
From 100-17=83
To 95-17=78
Dealing 22% of your dmg vs dealing 17% of your dmg, it’s still
22/17=1.294
29.4% more dmg than without sunder, at minimum.
Or it could also mean dealing dmg, versus not dealing dmg at all in case of unbroken immunes.
+sunder = more dmg = better . thx