Is spell penetration usefull or useless in pvp?

[Allahlas-sulfuron]

I was checking bis stuff for mage frost in p2 pvp.
In one bis list, they just take spell pen cloak enchant by default and that’s all (total 20).
In another one, they take cloak enchant + new pvp ring + 3 blue gems (x10) so a total of 60 spell pen.
So which one is the best ?

For each class, here is the spell resist you need to counter specific talents/spells (at least what i known and not counting basic resistance which seems to be 4 for each race and 14 for specific buffed resist race).

war : ?
pal : +70 (frost aura resistance)

hunt : +120 (frost resistance)
sham : +60 (frost resistance totem)

rogue : ?
drood : +25 (mark of the wild)

mage : +18 (frost armor / mage armor)
priest : ?
warlock : +70 (master demonologist)

Well the main goal i guess is to cover mage armors and warlock passive buff and maybe drood buff.

So what’s the best thing to do about spell penetration ? :
*just take 20 with cloak as a default enchant
*take 25 to cover mage armors + basic resistance
*take 30 to cover drood buff + basic resistance
*take 50 (cloak enchant + ring + 2 blue gems) because you need 2 blue gems anyways
*take 70 (cloak enchant + ring + 4 blue gems) to counter warlock passive

Thx for replying if you know how good spell penetration is for pvp.

[Зокник-flamegor]

Penetrating your opponent is always useful in PvP, in more ways than you can imagine.

[Roffejow-razorgore]

You’re pretty much spot on in your analysis. Some classes want more spell pen than others, for example a lot of classes/races have built in Shadow Resistance so getting spell penetration as a warlock or shadow priest is possibly more importan than getting it on an elemental shaman.

Basically you’re trying to remove any RNG elements from the game by having spell penetration, how much you need is entirely up to you but the consensus is 60 spell pen is what you should aim for.

[Allahlas-sulfuron]

Yeah, i agree with you somehow but if you look at wowhead guide for frost pvp mage p2,
they completely ignore spell penetration. Even for the new epic pvp ring, they don’t take it altough it has good stats.
They just take cloak enchant by default because all cloak enchants sux for casters anyways.
Wowhead is generally right so idk

P.S : sorry can’t insert links…

[Narcind-ragnaros (Narcind)]

I’m going to be running 55 this season

[Allahlas-sulfuron]

why 55 ?