This is an update to this post, taking into account some factors I’d forgotten.
For people who don’t want to follow the math, here’s the conclusion up-front: Given items of equal quality, gearing for Intellect is better than gearing for mp5.
Read on to find out why!
Introduced in patch 3.0.2, there are a number of new/revised sources of mana regen that are based on your total mana, and therefore scale directly with Intellect:
This is the new paladin spell at level 71; it restores 25% of your total mana over 15 seconds with a 1 minute cooldown (and a debuff to healing done).
This is the new raid regen buff granted by Shadow Priests, Retribution Paladins and Survival Hunters. It “causes up to 10 party or raid members to gain 0.25% of their maximum mana per second” whenever the priest, paladin or hunter uses a particular ability.
In addition, if you happen to raid regularly with a resto shaman, the Mana Tide Totem restores 24% of total mana over 12 seconds.
Doing the Math
To see how these balance out against mp5-based regen, let’s look at the value of 500 Intellect. (Note that I won’t be assuming the presence of Blessing of Kings, as you may not have access to it – and with current gearing levels it’s inferior to Blessing of Wisdom for regen anyway.)
500 Intellect on gear becomes 575 Intellect in play, thanks to Divine Intellect. 575 Int is worth 8625 mana. Assuming regen abilities are used on cooldown, on 8625 mana:
- Divine Plea can return 2156 mana per minute, equivalent to about 180 mp5.
- Replenishment can return up to 21.56 mana per second, equivalent to 107 mp5. This is dependent on uptime; 100% uptime is fairly unlikely.
- Mana Tide Totem can restore 2070 mana every 5 minutes, equivalent to 34 mp5.
500 Intellect therefore gives anywhere from 180-321 mp5, depending on your group composition and the uptime of their regen abilities.
However, looking at the item value of Intellect vs mp5, 500 intellect costs you the same itemisation budget as 200 mp5, which is only 20 mp5 more than the mana return of Divine Plea alone.
Illumination and Crits
That increased intellect has another effect: it increases your crit chance, which increases your mana return from casting spells. This is a lot harder to model, because the mana returns from crit rating are very variable, depending on your spell choice and casting frequency. However, doing some rough napkin math:
500 Int on gear becomes 575 Int in play for a holy paladin; 575 Int equals about 3.45% spell crit, according to this Elitist Jerks post.
Using a very rough casting model (which assumes that you’re using about 60% Flashes of Light, 20% Holy Lights and 20% Holy Shocks; that you’re keeping up Sacred Shield on one target, Beacon of Light, and Judging once a minute for Seals of the Pure; and that your Haste compensates for time lost to positioning), 1% crit chance restores about the same amount of mana, over time, as 10 mp5. This assumes near-constant casting, which is typical of a paladin healer; however, even if you’re spending up to 40% of your time not casting, 3.45% spell crit still provides as much mana return as 20 mp5.
The Bottom Line
Assuming you use Divine Plea on every cooldown, and that you spend at least 60% of each fight casting, gearing for Intellect gives you as much mana return as gearing for mp5. In addition, gearing for intellect gives you extra mana return from Mana Tide Totems and Replenishment if you have access to them (up to 78% extra mana return, in fact). And, finally, gearing for intellect increases your healing output as well, by increasing your spellpower (via Holy Guidance) and your crit rate.
Don’t eschew mp5 completely.
Yes, gearing for intellect is better than gearing for mp5, assuming items of equal quality. However, you’re often not choosing between items of completely equal quality, and you shouldn’t disdain mp5 to the point where you’re discarding otherwise-excellent items just because they have mp5 on them. Mp5 is not a dirty word – it still does the same job it always did, it’s just that now Intellect does it better.