Open this tool with geogebra (http://www.geogebra.org/)
To learn more about the math, behind read these two sources:
http://www.wowwiki.com/Armor
http://forums.elitistjerks.com/topic/22516-dps-compendium/
(this link also has a list over all armor values for all bosses in T5 and T6)
This tool helps calculate the benefits of arp. Given the non-linear nature of armor damage reduction, X arp will mean different things at 0 arp and 4810 arp (all basic debuffs and executioner applied).
tldr: the soft cap of item arp is 1390.
This is when a boss with 6200 armor has none left after all debuffs, executioner and item arp has been applied.
At this point you will do 58.73% more damage against a 6200 armor boss and 51.42% more against a 7700 armor boss, compared to no arp at all.
Note: reaching the arp soft cap will give a relative 13.17% and 11.53% damage increase on 6200 armor and 7700 armor bosses respectively, compared to just using debuffs+executioner.
Terminology:
Absolute: your damage increase compared to no arp.
Relative: given the current arp; your damage increase by adding X new arp.
| Armor |
6200 | 7700 | ||||
|---|---|---|---|---|---|---|
| debuff | arp | cumulative arp | rel |
abs |
rel |
abs |
| 5xSunder | 2600 | 2600 | 18.36% | 18.36% | 16.60% | 16.60% |
| Fearie Fire |
610 | 3210 | 04.50% | 23.70% | 04.10% |
21.30% |
| CoR | 800 | 4010 | 06.28% | 31.46% | 05.62% | 28.15% |
| Executioner | 800 | 4810 | 06.70% | 40.26% | 05.95% | 35.77% |
Ex. you win Stormrage Signet Ring (http://db.hellground.net/?item=32497, 126 arp) one day, how much benefit does the arp give you?
| Armor |
6200 | 7700 | |||
|---|---|---|---|---|---|
| comment | cumulative arp | rel |
abs |
rel |
abs |
| all debuffs + executioner | 4936 | 01.07% | 41.75% | 00.95% | 37.05% |
The total benefit of item arp
| Armor |
6200 | 7700 | |||
|---|---|---|---|---|---|
| comment | cumulative arp | rel |
abs |
rel |
abs |
| all debuffs + executioner | 6200 | 13.17% | 58.73% | 11.53% | 51.42% |
| all debuffs + executioner | 7700 | 13.17% | 58.73% | 27.37% | 72.93% |
For completeness; the numbers on expose armor. Here we assume 2/2 improved expose armor and that it replaced 5xsunder, giving it an arp of 475.
| Armor |
6200 | 7700 | |||
|---|---|---|---|---|---|
| comment | cumulative arp | rel |
abs |
rel |
abs |
| all debuffs | 4485 | 03.87% | 36.55% | 03.45% | 32.56% |
| all debuffs + executioner | 5285 | 04.14% | 46.07% | 03.66% | 40.74% |
| last 475 arp for a 6200 boss | 6200 | 04.50% | 58.73% | 03.94% | 51.42% |
| last 475 arp for a 7700 boss | 7700 | 00.00% | 58.73% | 04.50% | 72.93% |
Conclusion: arp is important, arp debuffs are very important.
The one time I did Magtheridon on hellground, I (prot war) was stuck at a cube and we had a paladin tank him. There was a blue geared pvp arms warrior with us. He did not apply sunders, neither did any of the other dps warriors but this guy was obviously bottom of recount.
He should have applied sunders, is all i'm saying.