Saturday, January 08, 2011

Detailed Tanking Stats

Once upon a time the only tanking stat that really matter was maximum health. Sure, armor was good and you wouldn't say no to avoidance and threat stats but when given a choice it was all stamina all the time. If you had a socket to stick a gem into you put stamina in there, no questions asked. Imagine my surprise then when I wanted to get a stamina gem cut yesterday and nobody had the pattern. Apparently the 'mana matters' world of Cataclysm has changed things enough that everyone wants other stats instead. I got someone to buy the pattern for me and cut my stamina gem regardless because I'm still a fan. But the question is, should I be a fan? My mastery scales with stamina and mastery is my favourite rating so it seems like if any tank wants stamina it should be me. But, should I like stamina?

Also, I recently put on the Darkmoon Faire tanking trinket, replacing my old normal Putricide armour trinket. Now, that trinket has more armour than the new round of armour trinkets does, so it's entirely possible it's just better than current trinkets. The question here then is how good is armour relative to stamina and dodge?

Well, as a tank, what am I trying to accomplish with my gear? There are 3 different things I could be trying to accomplish:
  • Inflict more damage to the enemies, increasing my threat and killing them faster.
  • Save healer mana.
  • Stay alive in dangerous situation.
The first option has generally been ignored in all my time tanking. I've never really had a problem holding aggro assuming the DPS let the mobs get to me (and if they don't then no amount of strength on my gear will matter) and that has held true so far in Cataclysm. If I get to stick a Rune Strike into a mob I get to keep it. If I don't then I have troubles. The solution here isn't to gear more threat stats, it's to just hit Rune Strike. As far as damaging the boss goes I do what I can for sure (I specced unholy with gargoyle and all the pet talents last expansion to do more damage) but it hasn't seemed critical to sac other stats for damage at this point.

The second option was relevant WAY back in the MC days (I geared avoid back then and stacked defense to try to get uncrittable back before anyone else did and I remember some healers were able to keep me up by changing how they healed and others just threw all their mana away) but hasn't been relevant since. The claim now is it's relevant again. I'm honestly not convinced. Healers certainly complain about mana more now than they used to and in early heroics I spent most of my time at medium to low health. But now, in raids? I'm full most of the time and if I'm not full I feel like I'm in real danger of dying. In heroics I used to hit cooldowns to try to save healer mana because I didn't feel like I was going to get spiked out. In raids I definitely feel like there are lots of spots where I could die and that I need to save my cooldowns just to live. Healer mana may matter a lot more in terms of how they handle raid damage and such but it feels like as a tank I just get spammed up reasonably often.

The third option I like to quantify in terms of what happens on the way from full to dead. Last expansion in particular I likened my health to a trinary system. Either I was at full life, or I was almost dead, or I was dead. Some people took this to the extreme and cared solely about "Effective Health" which took armor and health into account and completely ignored avoidance entirely. I've been a bigger proponent of "Tank Points" which take a long term look at how much damage you expect to have to take in order to be killed. A dodged attack absorbs the full amount with TP and is worthless in EH. The reality is probably somewhere between the two extremes and I tried to account for that in TBC with my own TPish program by adding in a parameter for spell damage that couldn't be avoided with dodge or armour and just cared about health. (Resists too, if the fight had enough magic damage.)

Finding the balance between those three things is non-trivial. I've tended towards just caring about the third weighting and assuming everything will work out fine with the other two. I think that model was clearly right in the last expansion and that Blizzard is claiming to be trying to change things this time. I'm not convinced they've succeeded but I can certainly find a value for every stat according to each of the three valuation systems to assign a relative ordering based on what I seem to be falling behind on.

The incremental value of each stat depends on my current stats. This is true because some stats interact well with each other and because some stats provide diminishing returns. Some stats have caps; getting more hit than the cap is useless for any of the three options. I will be comparing the value of stats according to how much a rare gem of that type would grant. For armour I will work out the equivalent amount based on the 346 trinkets.

Increases my maximum health which increases my time to live between full and dead. Increases the amount healed by my base Death Strike which generates threat from healing, which puts up a shield which keeps me alive longer, and which saves healer mana by healing myself and preventing damage with the shield. It also increases the amount I get healed by Rune Tap which has similar implications for threat, mana, and survivability. I believe it also increases the base health of my blood worms which increases the amount they heal which could save the healers some mana. Increasing maximum health also increases attack power from Vengeance which increases threat. 

60 stamina is worth 756 health. Assume half of my Death Strikes would benefit from a bigger base and that I use Death Strike every 12 seconds. Then every 24 seconds I gain 53 health and a shield for 59, which is about 4.667 healing per second and 2.208 threat per second. Say I Rune Tap once a minute, then it also adds an extra 7.56 healing and threat per second. Blood worms seem to get about 25% of my extra hp as hp themselves and heal for 5% of their hp per stack. They explode at around 7.25 stacks every 15 seconds, so this adds an AE heal of 4.568 healing per second per target. Vengeance caps at 10% of my max health, so assuming I maintain a full Vengeance stack (requires taking 18k/s incoming damage which is not a given) I'd also gain 75 AP. Working out what that is worth is more effort than I want to put in, so I turned to BloodSim and ran a sim with about my stats and then again with some extra AP. It claims 1 AP is 3 TPS for me, so the extra 75 AP would be 225 threat per second.
  1. 235 TPS, ~100 DPS
  2. Assuming worms hits 2 people and none of the healing I gain is ever wasted, 21 HPS.
  3. 12 ADPS, 756 max hp.
Flat reduction of all incoming physical damage that isn't avoided in some other way. By comparing ilvl 346 trinkets it looks like you now get 2.664 armour per stamina in stat points on an item. So, to fit my comparison, I need to account for 213 armour. My runeforge weapon enchant boosts this armour, so 222 is the real compare number. Compared to my current armour this will reduce all incoming physical damage by 0.333%. Assume I'm getting punched for 34k every 2 seconds and I'm flat out avoiding 31% of incoming attacks. As such, it would prevent 39 damage per second. Armour also adds attack power for DKs, so I'd gain 7.1 AP from the armour for about 21 TPS.
  1. 21 TPS, ~10 DPS
  2. 39 HPS
  3. 39 ADPS
Dodge Rating
Spiky reduction of incoming physical damage. With my current dodge rating and agility levels I'd gain .1813% dodge from 40 dodge rating. Again assuming an incoming swing of 34k every 2 seconds this would prevent 31 damage per second. 
  1. No effect
  2. 31 HPS
  3. 31 ADPS
Parry Rating
Spiky reduction of incoming physical damage. With my current parry rating I'd gain .1742% parry from 40 parry rating. Again assuming an incoming swing of 34k every 2 seconds this would prevent 30 damage per second. 
  1. No effect
  2. 30 HPS
  3. 30 ADPS
Mastery Rating
Makes my Blood Shield better. 40 mastery rating is .2231 mastery, which adds 1.7849% of my Death Strike heal into the Blood Shield. Assume I land a Death Strike every 12 seconds and that half of them are for base (same assumption as for Stamina above) and we'll give twice base for the other half. I believe I'm around 180k buffed hp right now, so the base Death Strike is 12600 and double is 25200. So 40 mastery gives me a shield of 337 every 12 seconds or 28 damage prevented per second. 
  1. No effect
  2. 28 HPS
  3. 28 ADPS
Haste Rating
Improves rune regen rate which increases amount healed by Death Strike. It also increases my threat in pretty much all ways since it increases my melee swing timer and lets me pump through the same proportion of extra everything. I guess it doesn't improve my dots or reduce the cooldown on rune tap so it's not quite a straight proportional improvement but it should be close enough. 40 haste rating would add on an extra .3124% haste to my existing 20.39% haste. This would bring my rune cooldown from every 8.3063 seconds to every 8.2848 seconds. This is a .2595% increase to everything. A quick look at the Omnotron encounter shows I have about 7k DPS right now, so a .2595% increase to that is an extra 18DPS and around 36 TPS. As well that would increase my Death Strike healing/shield from the current 3323 HPS by the same ratio, or a gain of 8.6 HPS. This would help the threat as well by just the heal, or an extra 4 TPS.
  1. 40 TPS, 18 DPS
  2. 8.6 HPS
  3. 8.6 ADPS
Hit Rating
Makes my interrupting and debuffing more consistent on top of increasing threat. Since runes aren't spent if the ability misses and I'm not GCD capped it's hard to work out the actual gain from hit rating. Currently on a boss I miss 4.98% of the time with melee attacks and 13.46% of the time with spells. 40 hit rating improves the melee hit chance by .33% and the spell hit by .39%. These are bigger numbers than the haste ones so theoretically if my resources were spent hit would be better than haste for everything. But they aren't. Missing a death strike is bad if I get pushed from a big death strike to a base death strike from the delay (or if I die from the delay) but really hit just isn't great. I do want to cap it out if possible to make sure my interrupts hit, though.
  1. Unclear
  2. Unclear
  3. Unclear
Expertise Rating
Right now I'm exactly at the point where dodges are gone. 40 expertise rating would decrease dodge/parry each by .33% (same as melee hit) and doesn't help spells at all. So up to the dodge cap it's twice as good on melee and worthless on spells as hit it. After the dodge cap it's just worse than hit. And it isn't needed for interrupting spells or applying debuffs, so it's not very good at all. I wanted to get up to the cap to help  Death Strikes be more consistent, and I'm there, so I really don't think I want to work on removing more parries.
  1. Unclear
  2. Unclear
  3. Unclear
Crit Rating
Increases threat and has no impact on surviving at all. (Death Strike heals can't crit.) I appear to crit right now on 2% of my abilities (7% on some of the abilities that are glyphed to crit more). 40 crit rating would give me an extra .2231% crit. Averaging things out a bit and assuming about 4% of my stuff crits now I'd be going from 1.04 to 1.042231 or an increase of .2145%. This would be about 15 DPS and 30 TPS.
  1. 30 TPS, 15 DPS
  2. No effect
  3. No effect
Part dodge rating, part crit rating. 40 agility gets improved by mark, so it's really 42 agility. 1 agility is worth .4103 dodge rating (.4308 post mark) and .7357 crit rating (.7724 post mark). 
  1. 23 TPS, 12 DPS
  2. 13 HPS
  3. 13 ADPS
25% of strength goes to parry rating. Also, strength is worth 2 AP each. Strength gets buffed by mark and Abomination's Might so 40 strength is really 42.84.
  1. 257 TPS, 129 DPS
  2. 8 HPS
  3. 8 ADPS

Every fight is different, of course, and the relative ranking of mastery to dodge depends a lot on the fight. One with spiky spell damage and reasonable melee damage favours mastery heavily. One with brutal melee swings (like Chimaeron) favours dodge rating with mastery being completely useless. I can also get better with my Death Strike timings which makes mastery, stamina, and haste better compared to armour and dodge. Stamina is oddly my second best threat stat (makes me wonder about the Vengeance capping assumption) and is a pretty good avoid stat too, plus it adds to max hp. I definitely feel like at the present time I should keep stacking stamina.

But what about Unidentified Organ? How good is 1890 armour and 240 stamina compared to 193 dodge, 128 mastery, and a cooldown use or 482 stamina and a cooldown use?

Organ - 1126 TPS, 489 DPS, 430 HPS, 394 ADPS, 3024 max hp
Darkmoon - 239 HPS, 239 ADPS, last stand use
Vial - 1887 TPS, 803 DPS, 169 HPS, 96 ADPS, 6073 max hp, dodge use

It feels like I should probably use Vial and Organ, sadly. If I had a heroic Organ it would be even better. 

1 comment:

Sthenno said...

A lot of this goes with my gut feeling assessment of stats. For Death Knights stamina and mastery just seem better than avoidance.

That being said, stamina only affects death strike heals if you are relying on the minimum. If you actually get hit for more than 28% of your health in the 5 seconds before a death strike, then your maximum health has no impact on the amount the death strike heals. I'd be interested to find out how often this is the case.