Iyunzusto wrote:
Say someone has 15 fire resistance, your spell might look like this to them when it hits:
256(67 resisted)
I believe arcane subtlety reduces that (resisted) amount. So if you have 2 talent points in arcade subtlety, their effective fire resistance becomes 5 (15-10). The damage in this case may read something like this:
296(27 resisted) or some such (the resistance value is not the amt of damage reduced)
Actually, that's a little off.
Resistances happen in 4 possible states(5 if you count no resist): 25% 50% 75% 100%
If we assume that Enemy resistance is capped out(75%). That means that you'll get a combination of the states such that it averages out to be 75% in theory. Obviously, in practice that means you'll get massive partial resists almost all the time, and a fair number of full resists.
Now, let's assume you have enough spell penetration to reduce their resistances to 50%. You will still get all the resist states, but you'll likely be getting half resists most of the time, and a lot fewer full and 75% resists than before.
That, of course, is before you start looking at binary spells. Binary spells have 2 resist states: 100% 0%
Perfect example of a binary spell: Frostbolt. The reason being is the added effect. You cannot partially resist the effect, so they had to make it so that you either do or don't get the effect.
Same situation: 75% resistance to frost. 3/4 of all frostbolts will be full resisted. 1/4 of all frostbolts will not be resisted at all.
Iyunzusto wrote:
From my experience, it has nothing to do with the number of times an opponent resists a spell completely. That's tied to level vs your level.
Full resists occur from two different points: Resistance type resists and Miss type resists. Level difference and +spell hit gear affect the second type, as do the talents Arcane Focus and Elemental Precision.
Now the important thing to note is that your PvE enemies will indeed not have much reduceable resistances, so you don't need too much. However, a little doesn't hurt. Throw a Spell Penetration to cloak on(what other enchant you putting on there? Armor? Agility? Subtlety is the only other one I'd say even consider except on resistance cloaks.) and pick up the Arcane Subtlety(I mean, where else you gonna throw the points?) and you have a good 30 or so. That number is near ideal in most situations, so don't worry about stacking much more than that(though, if you happen to pick up gear that's otherwise good that has it, then it's gravy).
Now, an important thing that was mentioned in the thread Gagady linked was the Nightbane fight. Sounds like that fight has some decent fire resistance, and not everyone runs with a 'lock, so that's one situation where it wouldn't hurt to have more spell penetration.
Tannar hit the nail on the head in that thread, kinda.
Quote:
Spell penetration, totally useless in pve, warlock curses do the job, and bosses have a unreducable resistance to all schools, i dont remmeber but i think it was 30.
If you're only running with one lock who is putting up Shadows(for himself and the Shadow Priests), then you'll find that you might just need more penetration than the little bit the talent and the cloak enchant will give.