The attack power component of any tank mastery at level 20 (except DH cuz they unlock later) is 1 point = 0.22% extra attack power.
What you have to do to know which stat will be more valuable is to write down your current agi / mastery
without the ring and do the following formula :
"a
" is your current agility stat, "m
" is your current mastery value (i.e. the damage it adds for instance 22% attack power would be a 1.22 multiplier), "ar
" is the agility value after equipping the ring and "mr
" is the new total mastery value after equipping the ring (ex : if you add 8 mastery to a current 32 you go from 1.1504 to 1.168)
1 :
(ar * mr) / (a * m) = how much more damage does your extra agility grant you (substract 1 then multiply by 100 to get a result in percent)
For an example :
Lets assume a start of 220 agility and 40 points of mastery (or 16.8% attack power / 8.8 points more than the baseline of 8%)
Lets assume a ring with 4 agi and 5 mastery and another ring with no agi and 14 mastery
We'll say the other secondaries are something like 5 and 7 haste so the change is minimal.
For both rings
a = 220 and
m = 1.168
For the agi ring :
ar = 224 and
mr = 1.179
We get : (224 * 1.179) / (220 * 1.168) = 1.02777 or around 2.78% more damage
For the mastery ring :
ar = 220 and
mr = 1.1988
We get (220 * 1.1988) / (220 * 1.168) = 1.02636 or around 2.63% more damage
Pretty similar for our example but just know that the more agi you have proportionnaly to your mastery, the worse the agi ring gets and vice-versa.
If you want me to run the calcs give me the numbers and I'll do so gladly.
Btw I'll link my old mastery guide, the first masteries aren't as in-depth and I forgot to mention the baseline mastery on some of the first calcs but it's pretty accurate and will hold up until the next changes in mastery which wouldn't be surprised to see happen soon with the xpac :
https://xpoff.com/threads/wow-tww-a-mastery-breakdown.100333/
Might help idk
Gonna say it again but this calc does not take into consideration the other secondaries on the ring but the method is basically similar for every secondaries, you'll just have to add an
h and
hr for haste for example, it'll give you more accurate numbers.
Also, don't freak out too much over 0.1% extra damage as it doesn't mean anything at level 20. Maybe 1 more mastery will be better than 1 more haste but maybe those few extra points of damage will go to waste against an enemy of relatively low HP compared to our damage output. The lower the number, the less reliable it'll get.
