Readers of this article may wish to review the one at EJ to ensure that you’re getting both sides of the story (the EJ article goes into a massive amount of detail and is possibly the best priest healing document I have read).

http://elitistjerks.com/f77/t97934-wotlk_healing_compendium_v3_3_3_icecrown_citadel_beyond/

– Replenishment
– Rapture
– Mana Tide
– Shadowfiend
– Divine Hymn (not a joke when it restores 500 mana / tick)

I’m sitting unbuffed at just over 20k mana, and in raids top just over 25k w/ buffs. With just replenishment running, I’ve yet to run OOM (have cleared all current content except 25-man Malygos, hopefully going down this week) and am never in group w/ resto shaman’s totems nor do I ever get an innervate. Unbuffed crit is about 22%. I think 20% is ‘enough’ but when I build my haste up further (currently only about 6.5% from gear) I’ll try to drive that more towards 25% to keep more of that delicious Divine Aegis up.

Any thoughts on consumables? Haven’t done the theorycrafting because I’m terrible at it, but I’ve been using the old Flask of Distilled Wisdom on progression content and loving it.

0.375 x 16 SPI = 6 mp5

Point taken about the importance of int, I don’t think anyone here would disagree that int is king for the disc spec.

If someone is serious about min/maxing all of their stuff, they will care about the MP5 vs. Spi issue, if only because you’ll be slotting an Insightful Earthseige Diamond for your meta slot, and it will require you to slot at least one blue gem.

So, I feel like I’m missing something here. I agree with your formula —

0.3* 5 * 0.005575 * Spirit * Square_root ( Int ) = Mp5

but still don’t see where you get the 1520 INT from. If 1520 is the break even for the 16 spi gem vs. the 6 MP5 gem when inside the five second rule, then if I plug all of those numbers in, they should be equal. What I get is:

5.216 !- 6

If I plug 2010 in, I get

5.999 ~= 6

Either way, I don’t see myself getting to those kind of int numbers (1500 or 2000). I am sitting at about 1080 right now with a mix of heroic gear, Naxx 10 pieces, and Naxx 25 pieces (the Naxx pieces are not BiS for Naxx). Without raid buffs, that puts me at a little under 20K mana pool. What I’ve found is that is enough to get through all of the raid encounters I’ve seen so far w/o going OOM. I’m using the scenario of healing the offtank on Patchwerk in Naxx 10 as my “worst case” — but I’ve only been through about three and a half wings of Naxx on normal or heroic so maybe I’ll change my mind. However, it seems like 20K mana is some kind of sweet spot for Rapture to proc and return mana. So I’ve started to prioritize gems and enchants as I get new pieces for spellpower, crit, and haste instead of pure int.

0.3* 5 * 0.005575 * Spirit * Square_root ( Int ) = Mp5

1520 INT is the value where a 16 spi gem beats the 6 mp5 gem while casting. If you can get any FSR time the value of mp5 is even less.

At 1000 INT, 1 spirit = .881 mp5 out of the FSR. 1000 INT is nothing, that is the “I’m still getting gear to go to Naxx” stage. I have 1 item from Naxx and only some of my heroic BiS and I’m personally at 1141 INT unbuffed.

Assuming Kings and 5/5 Enlightenment, at 1716 INT SPI is better than mp5 regardless of FSR.

1000 INT for DIsc is actually 1150 due to MS. so assuming Kings and 5/5 Enlightenment 1 point of Spirit is 0.005575 * 5 * sqrt(1150) * ((0.3 * 0.95) + 0.05) * 1.1 * 1.05 = 0.3657 mp5.

mp5 is not affected by anything, while spirit is affected by both talents and buffs.

My point is that you should not be picking gear based on spirit or mp5, ever. But if you have to, depending on your INT, you would pick one or the other if that is the only differing factor.

When it comes down to it, if you are having mana issues, you should be looking to get more INT not mp5 or spirit.

1. There is a break even for OFSR regen at Int = 1287, no matter what your spirit is (e.g. at that point, adding one point of spirit has the same mana regen as one point of MP5)

2. For a disc spec, where you expect to be IFSR all the time, the break even point — assuming you spec’ed into meditation — is more like 10,000. However, Blizz doesn’t budget the same amount of weighting for MP5 as for spirit. If we look at the gems avail in game today, the blue-quality spirit gem is +16 and the blue-quality MP5 gem is +6. So we might make an assumption that Blizz is weighting spirit at a 2.67 ratio to pure MP5. If you make that assumption and work the algebra again — asking at what point does adding 2.67 points of spirit equal adding 1 point of MP5 for IFSR regen, I get a number around int = 2010.

So my conclusion is that there is a break even, but it is pretty far away — having int of 2010 works out to something like a 34K mana pool.

If someone wants to check my math, here is the starting equation:

MP5 = 5*sqrt(int)*spi*b

where b = level 80 coeff, 0.005575 The formulas you see on wowwiki have another term in the equation, but it only equals 0.005, so it I am dropping it because it is in the roundoff error

Further assume that we are always inside the 5 sec rule, so the actual MP5 is 30% of the OFSR MP5 above. Finally, assume that we’ll see about 2.67 points of spirit on equivalent iLvl items for every point of MP5 (use my gem example above: we could either gem for +6 MP5, or +16 spirit).

So solve this equation for “int”:

.3*5*sqrt(int)*spi*b + 1 = .3*5*sqrt(int)*(spi + 2.67)*b

The left side of the equation is just the IFSR mana regen, plus 1 point of MP5. The right hand side fo the equation is IFSR mana regen, when you add 2.67 points of spirit.

1 = .3*5*sqrt(int)*2.67*b

int = (1 / (.3*5*2.67*b) )^2 which is approx int = 2010.

Usual disclaimers apply, and it is late and I am doing this in a hurry. But, my conclusion is that if I am spec’ing to be in the five second rule all the time (e.g. I care more about IFSR mana regen then OFSR mana regen), then all other things being equal, I would never choose spirit over MP5.

Need to cast on the move? PW:S, PoM, Both will provide a bigger heal (or mitigate more damage) than a Renew will.

I’m not saying Renew is useless, but it has simply scaled worse on the road to 80 than every single other ability you have. There can be a time and place to use it, but in general those are few and far between.

In regards to my mp5 and spirit comment, mp5 is ok until you hit the break even point with your INT. Off the top of my head that is around 1500 INT raid buffed at which point spirit will return more mana than mp5 will point for point. 1500 INT is an easy number to reach. I don’t even have my BiS from heroics much less raids and I’m sitting over 1000 INT and buffed am over 1200.

Disc priests want INT and SP primarily. You want about 20% unbuffed crit and a fair amount of haste. Beyond that its mainly personal preference and playstyle that will dictate how you gear. In general though, you will never select a gear upgrade based on how much mp5 or spirit it offers.

Its also a common misconception that Disc healers should be stuck on Tank duty. To pigeon hole us like that is doing a disservice. While we can excel at keeping a Tank up, we can also excel at just about every other healing duty you throw at us.

Remember it’s not always about the raw numbers but about playing to the situation.

Since we tend to cast frequently there is not much time to regenerate mana when not casting and that means another stat also becomes very handy for us – intellect. Having a large mana pool from start that you slowly empty until it’s dry can be as good as having a smaller one that you fill up along the way. That is especially true when the big mana pool also gives you benefits in the shape of more crit (which proccs our supersweet shields) and larger manareturns from Rapture. My guess is that this is what Cal was referring to above without giving any explanation. And in that sense he would be right. Intellect is the prime mana-stat of a discipline priest. It doesn’t however redeem spirit or mp5 worthless.

P.S. I’ll save the number crunching for another time but this should give you the general idea for the reasoning at least. D.S.