Does anyone have any information on the resist levels of enemies in AQ40 and Naxx? I'm talking mainly about trash mobs or boss mobs that don't have an "obvious" resist, but might have, say, 40 or 50 resist all that would go unnoticed most of the time. I ask because my guild has recently been discussing the merits of spell penetration gear which we all know is useless against mobs with zero resists. I had previously assumed that the majority of raid mobs did indeed have zero resists, but since we've brought up the topic, some members are saying they've always observed partial resists on the assumed zero-resist trash mobs or bosses. Now I don't think that zero-resist mobs can ever get partial resists, but correct me if I'm wrong as this would explain things. Otherwise, either people are making incorrect observations or most raid mobs have nonzero resists and hence spell penetration gear has a greater use. We're going to be testing it in the coming weeks, but I wonder if anyone has already done the work and can provide this information.

There's a partial resist mechanc that is similair to glancing blows. It's impossible to get rid of it, and I believe is a 5% reduction in damage on level 63 mobs. It only effects non-binary spells.

^^ edit: Do you have testing data to confirm this? Last I heard there was only anecdotal evidence for it. Also, does spell hit affect that glancing blow mechanic at all?

I have gotten partial resists on AQ40 trash pulls. Some of those partial resists have been with Curse of Shadows on the mob. That implies a starting resistance greater than 75. I've noticed the same results on Huhuran.

My understanding was always that raid mobs had sub-75 resists, but they did have some. With the relevant Curse applied their resistance was reduced to 0. This is definitely the case in MC (with the exception of some heavily fire-resistant mobs) and BWL. That seems to have changed in AQ40, however, which is exactly when I'd expect it to. That's when penetration gear first started coming out. There is another possibility, however.

There has been speculation, poorly tested and mostly anecdotal, that level-based resists have been placed on a sliding scale instead of being binary. That would make spell resists more like glancing blows, though there is currently no way for casters to gain casting "skill" like melee do weapon skill. The mechanic for spell skill was in beta, and probably is still there, they just haven't itemized for it. The fact no spell skill items exist lead me to believe the glancing spell solution is probably not correct. Then again, it wouldn't be the first time Blizzard left an itemization hole, so hey.

So, in summation: I believe the dev team has started placing over-75 resist levels on some or perhaps all raid mobs. This ensures that even with the appropriate warlock curse, mobs have some mitigation (besides level-based) against spell damage. It is, however, possible that partial resists are the result in a stealth change to level-based resists such that they function like chromatic resists. In this case partial resists based on level will be possible, and the average amount of mitigation the target mob has based on level will equal its resist percentage, separated into 25%, 50%, 75% and 100% resists over time.

In that case, spell hit should function for level-based resists exactly as penetration does for chromatic, in nice handy percent-sized chunks.

Hrm..if this is the case then the official WoW page on spell resists (http://www.worldofwarcraft.com/info/...sistances.html) is incorrect.

Wtb +spell skill ability.

i get partial resists in naxx against bosses with CoE with -30 spell penetration sometimes... sucks :/

There was extensive testing done on this static-partial resist phenomenon, on the EU mage boards. I linked it over the US mage boards a few weeks ago, but it seems to have decayed now. Anyway, the upshot is this:

Using full -resist gears and arcane attacks on Huhuran (with CoS), a mage tested partial resist rates. He observed a roughly 5% rate using over 100 -resist gear. This rate was statistically identical to all the other mages, using no -resist gear. Further demonstrations point to the existence of a flat partial resist rate not overcomeable with -resist gear (making this more a PvP itemization, 'cept for warlocks in Naxx, and the godliness of 5/5 Doomcaller).

My unanswered question is this: if -resists don't work (these are flat rates, not resistance-based resists), does +% spell hit help reduce the number of partial resists seen, due to this flat rate on lvl 63 mobs?

Question answered in another thread.

+spell hit no good either for this

Resist rates:

Binary spells- There are two rolls here. First to check to see if it hits (base hit chance + hit% gear, capped at 99%). Second to see there resistances to it ((resist rate - spell penetration)/400, for resist level 60, capped at 75%). Somewhere in that formulae is the level based resist. It's probably something that just adds 20 resists, just after the penetration calculation is done. Since penetration is capped at 0 resists...

Non-binary- Only one roll here. (Base hit chance + hit% gear - resist rate, capped at 99%). Only signifigant thing here is that +hit% gear can overcome resists, especially for PvP. And there is no level based resistance since that seems to be tied into the partial resist formulae.