Actually I've found it to favor arcane over deep fire. It is easier for me to convert all that mana I regen from moving around into DPS. I have some SS's I'll post later tonight of our VR kill last night (I'm not on my home computer atm). Meter was Me > BM Hunter > Arc Mage > Arc Mage. I use Imp blink to move around more quickly and AB spam a large portion of the fight.

Edit: To be fair our group consisted of 3 Arc Mages, 1 SP and an elemental Shammy.

I can't find them at the moment but I've seen some theorycraft on when 1 spirit > than 1 intel. I think it was in a 3 minute fight but don't hold me to it.

Well, I posted the gemming decisions I use myself as fire. I assure you the extra stamina is non negligible in hyjal/BT. The fights tend to include lots of AOE, which cannot be necessarily avoided (much less with blink !). Naj'Entus does raid-wide 9k attacks many times in the fight plus multiple 3k conical aoe, in addition to single targetted 5k impales (+ dot). Archimonde is a literal AOE fest (even worse if you have anyone die). In fact, most bosses in hyjal do extreme amounts of damage that cannot be prevented with blink.

In any case, worst come to worst, the difference is 30 sta, 12 crit -vs- 0 sta, 0 crit, 24 dmg

In a 0 minute fight 1 spi gives 16 mana via evocation while 1 int gives 15-17.25 mana, or with kings 17.6 mana for 1 spi and 16.5-18.75 mana per int with kings. Doesn't take long at all for the pure regen from spi to surpass int, even if you use 10/48/3 spec with molten armor simply moving a few times during the fight will make 1 SPI clearly superior to 1 int in terms of mana. Of course 1 int is also worth 0.22 spell damage, multiplied by 1.25 for an arcane spec buffed with BoK, +0.25X1.25 with mind mastery on top of the 0.22 (which is calculated from the increase in crit int provides).

6 stats to chest provides less than 500 mana on a 10 minute fight with 45% regen while casting casting 100% of the time using 1 evocation and having kings+arcane talents, 6 mp5 provides over 700. 6 int though gives 3.5 spell damage too. I currently have 150 HP on my chest but with gear getting upgraded and my HP going up as I get higher level epics, it's less needed to hit that minimum to stay alive in raids and will re-enchant it when I get 2/5 T5 and respec.

Overall in a 10 minute fight:
mana pots provide 100 mp5 or 12,000 mana
mana spring provide 5400 mana with 2/5 T4 and talents (could be a little off, but it's at LEAST 3600 mana with no 2/5 t4 and no talents)
Evocation provides several thousands more mana (never bothered checking exactly, not hard to caluclate based on spi regen formula) Remember to use spirit weapons/wand as they result in over 700 extra mana from evocation.
Shadow priest with 500-1000 DPS will provide 15000-30000 mana
If you regen 75 mp5 while casting it'll restore 9000 mana
Mana gems provide 4200 mana
You should start the fight with ~8-9k mana or so? 10k+ if arcane speced probably with my gear.

Add it all up and you get over 60k mana or so in 10 minutes. Even if your DPS is totally limited by mana supply and you could turn 1% more mana into 1% more DPS (which isn't really true as your "burn extra mana" cycles don't provide that efficiency but let's take the worst case scenario for a sec where you managed to burn 60k mana in 10 minutes without fully debuffed AB spamming) - Amount of needed for 1% mana increase is 11 spirit. Amount of spell damage needed to increase DPS by 1% is ~20-22 for most well-geared players.

If you're only able to burn that mana with AB then your DPM is ~1/2 so you need more like 22 spirit for 1%. If you use molten armor the amount of spirit needd for 1% mana increase is even bigger.

For int to increase mana by 1% you will need 32 int, however 32 int is also effectively 16.5 dmg increase which is ~0.8% more dps increase, so the actual amount of int needed for 1% increase if you really are mana starved for your NON-full-debuff-AB-spam rotation you'll need 17.9 int for 1% DPS. Of course again if you burn that extra mana with AB spamming you need more like 25 int for 1% DPS increase.

Interesting as it makes int actually about equal to crit rating point per point for a mind mastery specced mage, however mind mastery specced mages already lose DPS compared to 33/28 the way I see it as AM, while close, is just not as much DPS as fireball even if you lose AB DPS by having more +hit and no mind mastery, and you don't really get much in return by swtiching gems.

Of course this isn't totally accurate but just to give you an idea. To get more accurate results of comparing int to dmg/crit you need to get much better data on how much mana you have, how you're going to spend any additional mana and how much dmg/crit/hit you need for 1% DPS increase. It's very interesting though as apperantely int is far from pointless, and the "int instead of crit" gem idea isn't totally out of the blue, and might actually give a slight dps increase after more accurate calculations. All in all it's very hard to calculate the DPS increases from extra mana because of all these factors that need to be taken into account.

Excellent Post, Ty.

Not to nitpick, but 1 point of spirit will provide .11 spell damage from Divine Spirit + Blessing of Kings. I don't think this changes your calculations that much though.

Not considering the Focus proc from the meta gem, what are your (collectively) opinions on spell haste trinkets (NOT fixed spell haste from items)?
I've found they change the flow of my cast sequence and are only fully useful on pure AB spam fights (adding AGAIN to the mana drain, hehe.)

Also, quick question, stopcasting macros for Arcane Missiles on a clearcast, how would that be set up?

I had originally:
#showtooltip Arcane Missles
/stopcasting
/cast Arcane Missiles(Rank 10)
Didn't work for some reason, the icon on my action bars did nothing when I clicked it :\

You overvalue mana a lot for AB spam burn cycles.

Taking the numbers from my spreadsheet (40/18/3 spec), I get the following spell data:
Arcane Blast (cast 3 times) - 1.833s average cast time (1.5s, 2.166s, 1.833s), 3005 average damage, 303 average mana cost
Arcane Blast (cast 4+ times) - 1.5s cast time, 3005 damage, 573 damage
Fireball - 3s cast time, 3529 damage, 270 mana.
(This is assuming ~20% base crit, 1300 damage inclusing mind mastery, 2/5 T5, the mana cost is "talented mana cost minus mana return from MoE minus mana regenerated from spirit while casting that spell". Average damage includes misses and crits.)

Assuming 0.2s lag, your normal cycle (2*FiBa, 3*AB) has 12.5s cast time (11.5s + 1s lag), costs 1449 mana and deals 16073 damage.

Arcane Blast in a burn cycle is a 1.5s cast + 0.2s lag, so in those 12.5s you can spam AB 12.5/1.7 = 7.35 times.
That takes 4211 mana and deals 22087 damage. 2762 more mana used for 6014 more damage done.

In percent, it's 2762/1449 = 190% more mana used for 6014/16073 = 35% more damage done. That's if you replace all your normal cycles.
In reality, you will only add a few burn cycles. The extra damage per extra mana ratio will remain the same though, so for 1% more mana, you get (35/190)% = 0.185% more damage.

In the above calculations, you assumed +0.5% DPS with +1% mana. But as this calculation shows it's only +0.185% DPS per +1% mana, you need 2-3 times as much mana stats than what you assumed (take *2.5 for simplicity).

That puts you at ~55 spirit for +1% damage, ~22 spell power for +1% damage.

For the intellect calculation - taking your 32 int = +1% mana, 32 int then gives 0.185% DPS from mana and also 16.5 dmg = 0.8% DPS, so 32 intellect ~= +1% DPS.

For that spec and cycles, 1 crit rating ~ 0.826 spell power, so +1% DPS = 22 spell power = 27 spell crit rating.

Short Version
Extra mana that is converted into damage via Arcane Blast spam burn cycles has a conversion ratio of +1% mana => +0.185% DPS.
In that case, 55 spirit = 32 intellect = 27 spell crit in terms of added damage in a set time frame.

Edit: For 0.1s delay, you get +40% DPS for +194% mana, so you get about 10% more from your mana, so +1% mana yields +0.206% DPS.
That should be 50 spirit ~ 31 intellect ~ 27 spellcrit with these low cast delays.

When you use fireballs or AM fillers haste only gets slightly reduced effect compared to 10/48/3 as 2/3 of your ABs and most of your filler casting time gets benefit from haste. Although since 1.5s cast spells get nothing from haste it's not as effective. The relative effectiveness isn't too easy to calculate, but not impossible either. Another thing is with AM casting faster since your fireballs suck and they're the only filler you may toss in if your AM got hasted enough, it's even less effective than for 33/28 which can toss in an extra scorch after the 2 fireballs if you got haste (assumine some minimal lag, as with no lag at all it's very hard but very possible to get 2 fireballs and a scorch with no haste, but 3 fireballs isn't possible even with quag's eye haste even if it procced on your last AB). All in all haste benefits 10/48/3 the most, a little less for AB/fireball builds and a little less for AM users.

Try:

#showtooltip
/stopcasting
/cast Arcane Missiles

If you don't specify a rank it automagically uses the highest rank. Make sure you spell Missiles right as well, I always forget the second I.

I agree with the conclusions. For my calculations on 10 min fight I arrive at 4.8 spirit = 2.5 intellect = 2.3 spell crit = 1.9 spell damage.

This worked, thanks a lot!
Not sure what was wrong with the other one, maybe I misspelled something hehe O.o

You didn't have a space between "Arcane Missiles" and "(Rank 10)".

I don't in any of the other stopcasting macros I have...?
Curious.

I'm using a setup very close to this, and I'm an Arcane spec mage (47/14/0). I just had my 1st day of SSC run using an Arcane build (after getting 2/5 T5 last week). Here is my setup if anyone is interested:

1) 1 Shadow Priest + 1 resto shaman in party (Most important, imo)
2) 6% hit from gears and around 27% buffed.
3) 1218 unbuffed arcane damage (a bit low, since I put on a bit more stam). I was at around 1440 arcane damage with buffs (including shaman totem)
4) Around 325 raid buffed spirit with pot

Hydross Fight - AoE poison adds, Single target Frost Adds

Lurker Below - pretty standard fight which favors arcane due to having more thrash mobs and long mana regen time in between.

Tidewalker - I died at around 20%+ mark, and got battle rez after around 1 minute.

Anyway, I feel its possible to make arcane work on comparable level with deep fire for SSC. I'm not so sure about other places since arcane shines in AoE and aggro sensitive fights. The downfall is that I spammed a lot of Super mana pots just to keep up with mana cost.

Edit: I've yet to go to Fathomlord this week, and my guild has not downed Leotheras yet. However, I find Arcane spec outstanding for Leotheras.

Remember who you're comparing yourself to though, the mage with 8% was scorch spamming with a fireball average damage of 1700... Didn't do a deep analysis of your WWS but it really looks like your competition was subpar and the reason you made #1 was skill and gear more than spec. Would you do better with fire or 33/28? That's not something those WWS parses can say.

Also you were using TLC weren't you? (nature dmg) pretty bad on hydross as everything is immune 1/2 the time, might as well equip something else.

I'm not sure if the Spellfire set is the way to go for an arcane spec. Sure, it offers a fantastic spelldamage-boost, especially with the setbonus. But on the other hand you're losing a huge amount of stats compared to stuff like T4/T5, the robes from Nightbane etc. I'm not talking about a mere 20 stamina... It's more like a 100-150 stats-difference on those three slots, not considering Blessing of Kings.
I banked my Spellfire-stuff after getting my fourth piece of T5 and don't even consider switching it back. The 4pc-buff is up all the time once you AE or use AM.

From the comparisons I've done for full arcane Spellfire Robe and Spellfire Gloves are about in between T4 and T5, Spellfire Belt is best for slot until you're in Hyjal.

Did you factor in the setbonus? Can't see Spellfire Belt win over Belt of Blasting, though.

Spellfire belt is significantly inferior to the Belt of Blasting from all the theorycraft I did - for my gear, at around 1050 fire damage, 33% to crit and 10% to hit, it was a 25 DPS increase on Vontres spreadsheet, although obviously a loss of 10 stamina.

I didn't factor set bonus. I think the reason why we have different conclusions is that with arcane I'm hit capped, if I weren't then Belt of Blasting would better.

Let's have a look at it (socketed as Manly proposed):
Spellfire Robes - 17 Int, 10 Sta, 82 Damage, 32 Crit
Spellfire Gloves - 10 Int, 10 Sta, 60 Damage, 27 Crit
Spellfire Belt - 18 Int, 10 Sta, 60 Damage, 22 Crit
45 Int are an additional 11 spelldamage due to Mind Mastery.
Assuming 600 Int the setbonus gives another 42 spelldamage.

Equals 675 Mana, 300 Hitpoints, 255 Damage, ~94 Crit, 0 Spirit


T5/Blasting with the same gems:
Robes of Tirisfal - 36 Sta, 35 Int, 20 Spi, 75 Damage, 27 Crit
Gloves of Tirisfal - 26 Sta, 27 Int, 18 Spi, 41 Damage, 27 Crit
Belt of Blasting - 6 Sta, 0 Int, 0 Spirit, 64 Damage, 34 Crit, 23 Hit
52 Int are an additional 13 spelldamage due to Mind Mastery.

Equals 780 Mana, 680 Hitpoints, 193 Damage, ~102 Crit, 38 Spirit (another ~4 Damage )

Seems like I really underestimated the Spellfire-set and especially the bonus... the 4pc T5 should be enough to break it, though. The more hitpoints, mana, crit and spirit will probably outweigh the pure damage-advantage of Spellfire.


Kavan:
Even if you are capped on hit Belt of Blasting is still the better item on that slot if you don't factor the Spellfire-bonus in.