How do level-based resists affect Frostbolt? I haven't been Frost since they were discovered. Fire loses 6% to partials. Does Frost just eat 6% unavoidable resists (beyond whatever you would have had)?

Some findings shows that binary spells don't suffer from that penalty. Also, 6% is only valid for lvl 60 caster, at lvl 70 it will be 0.15*24/70~5.1%, assuming of course it is still 8*level_difference

Right, I'm updating for level 60 right now. Don't even feel like thinking about Arcane Blast.

Hmm, so +%damage bonuses stack multiplicatively, but +%crit damage bonuses (Spell power + Ice shards) stack additively?

From the testing I did a while back, that's indeed how it works. I assume it's still the same way.

No, you're getting confused by the different resists - which is very easy, given they make no sense.

On top of the standard level based resists and partial resist for resistances, which are as you say incorporated into the single resist roll for binary spells, there is an additional partial resist rate on non-binary spells, that equates to about 6% loss in damage.
There's no equivalent for this for binary spells - it simply doesn't exist, and isn't factored into the one resist roll at all. Our best guess is it's an artefact of some older part of the game, when the player had some control over their casting skills. When they removed that aspect of the game, and had your spell schools always be maximum value, they left in the partial resist rate for higher level mobs and can't / don't know how to remove it now.

Yep, thx. This was the part of interest:

"A Mage (level 60) fires a frost bolt at Yeti of Doom (level 63). The Mage is also wearing a total of +6% spell hit gear. Yeti of Doom has frost resistance such that he takes 50% from level 60 frost attacks. So, here’s the hit calculation:

0.83 (83% for +3 levels mob) + 0.06 (+6% spell hit) = 0.89

0.89*0.5 (50% damage from frost) = 0.445.

The game will roll a number between 0 and 1, and if it’s less than 0.445, the frost bolt will hit for full damage. Otherwise, a resist message will appear. "

So I'm assuming if it was using level based resists, at a 6% rate of partial resist, then the math for a frost mage with 16% hit against a level 63 target with no actual amount of frost specific resist would be:

0.99*.94=0.9306 ??

Just for theorycraft sake, if that were correct, could you compensate with more % hit?

22% hit ---> 1.05*.94=0.987

I don't know if the game would even let you do that though?


Edit: Ok, so based on what Mal said no need for this, unless you just wanted to compensate for it in pvp with frostbolt or something similar.

Last I checked, more hit percentage will overcome resistances on binary spells. I checked by dueling a friend using level 1 Frostbolt. Non-binary spells can not use hit percentage to overcome resists. It looks like there's a one-roll system on binary spells ( (Base hit chance + hit percent) * resist rate) and a two-roll system for non-binary spells ( (Base hit chance + hit percent) || Damage * (resist rate + level based resist rate) )

For those debating the binary resist rate: http://nullcode.org/~chris/ul/patchwerk_resists.jpg

From a couple months back, I was wearing max +hit gear. No Winter's Chill on him that day :(

Doesn't it just add 10% to your effective +dmg bonus? Making it effectively equal to (3/3.5)*0.95*1.1 = 0.896?

That's really a guess, though. Most of the things using the same mechanic are new to TBC as well:
http://www.thottbot.com/beta?e=Apply...8Penalty%3F%29

Out of the two you posted, I find it highly unlikely that it would be the first one. If +dmg coefficients are just stored in a lookup table (as there's no reason to compute them on the fly), that would require some weird implementation. Also, it doesn't really make sense. The coefficient of Frostbolt is 0.814. The 3/3.5 and the 0.95 are actually pretty meaningless in their own right.

That's what I originally assumed:

Empowered Fireball: 3.5 / 3.5 * 1.15 = 1.150
Empowered Arcane Missiles: 5.0 / 3.5 * 1.45 = 2.071
Empowered Frostbolt: 3.0 / 3.5 * 0.95 * 1.1 = 0.896

However, I've read (I think earlier in this thread, but it's been a few weeks) that in fact it is additive, not multiplicative:

Empowered Fireball: 3.5 / 3.5 + 0.15 = 1.150
Empowered Arcane Missiles: 5.0 / 3.5 + 0.45 = 1.879
Empowered Frostbolt: 3.0 / 3.5 + 0.1 = 0.914 (or the alternate method posted above -- but it does sound like it makes more sense this way)

I'm leaning towards multiplicative. Maybe the confusion is just coming from the fact that multiplicative and additive are the same for fireball. It doesn't make sense to me that they would let the gain from the empowered talent just "skip by" the normal coefficient of gain of plus damage.