This will just be a small post about the discipline talent Rapture. It's an awesome talent, and if you know everything there is to know about it, you'll be even better at using it to the max! So I thought I'd mention two good to know things about this talent.
How much mana do I need to gain mana on my Rapture proc?
This is a question which is very good to know the answer of. Let's first check out what Rapture does before the explanation and answer.
"When your Power Word: Shield is completely absorbed or dispelled you are instantly energized with 2.5% of your total mana, and you have a 100% chance to energize your shielded target with 2% total mana, 8 rage, 16 energy or 32 runic power. This effect can only occur once every 12 sec."
The highlighted parts are the ones that you need to think extra carefully about. So getting back to my first question up there, what do I mean by it? Well, since your spell Power Word: Shield has a mana cost based on your base mana, which is fixed, it will always cost the same, no matter how much mana you have. That means that it becomes cheaper and cheaper (will use up less and less of your total mana) the more mana you have. When completely absorbed, it returns 2,5% of your total mana. Total mana is something you can affect, it's a number you can increase. That means that the more mana you have, the more mana you will get in return from Rapture procs.
This in turn means that there is a point where you will get more mana in return than the spell actually cost to cast! You'll gain mana from your Rapture, at least once every 12 seconds. So back to the question; How much mana do I need to gain mana on my Rapture.
To me a Power Word: Shield costs 888 mana. With the disc talent Soul Warding (which every disc priest -must- have, or they're simply not disc priests), you'll get the mana cost on PW:S lowered by 15% to 666 mana (it's a sign >;) ).
So we need 2,5% total mana to be more than 666 mana. Now remember that I suck at maths, but I'll use this formula;
666 / 2,5 = 266,4
266,4 * 100 = 26640
So with 26.640 mana you'll go even steven on casting a PW:S if your Rapture procs. Any amount above this will result in a gain. And if your shield costs another amount of mana than my 666, simply use the calculation above to get your numbers. So something like;
Your shields mana cost / 2,5 = Y
Y * 100 = Your mana needed to go even
Is there some way to fool the Rapture proc?
Yes, in fact there is, I read about it over at EJ so kudos to them. Rapture was quite bugged before. Although it has always said to proc only once every 12 seconds, I know it took them quite a while to get this working. Now it actually seems they have (boo), but there is still a way to get around this. If you have alot of Raptures proc exactly at the same time, you'll get all the procs at once (and not just one like it should)! To make this happen you must A: Make alot of shields be completely consumed at once and B: Make sure Rapture isn't on its 12 second cooldown already.
In raids there are often fights with some sort of big aoe blast mechanic. Defile on LK is one example. That means you'll be able to anticipate when the entire raid will take a big blast, and exactly how much damage it will do. By shielding everyone in the raid before this blast, you can have all the shields be absorbed at once and gain all the procs at once. There are some things you need to think about here though.
First if all, if you have too much spellpower (aww, aint it a hassle), your shields might not be absorbed by the damage! And thus you won't get any procs. The only way to get around this is to downrank your PW:S to a rank more suitable to the amount of damage the skill does. So if Defile does say 3000 damage to everyone in the raid, try to use a shield as close to this number as possible (but slightly under it of course).
Secondly, to avoid having your Rapture proc on cooldown, you must avoid shielding those that take continous damage. Mostly the tanks, and anyone else being hit while your setting up your shield armada for the big bang.
Now this might sound like alot of buck for very little bang, and I agree that it might not be worth doing this unless you have mana issues. On fights like LK mana might (and probably will) be a problem (and priests aren't known to be able to waste mana anyway), so knowing about this method is good in any case. To me, having about 35000 mana in a 10man raid setting, this would turn out to be nearly 8000 mana optimally (shielding everyone but the main tank). And even if I only could get something lame like three shields to proc simultaneously, it would be more than 2500 mana. Definitely not cat shit.
Got any more questions or tips about these kind of things? Let's hear em!