Why do we use arcane blast only >93% ?

[EvilCalamari 0]

Is there some mathematical significance to 93% specifically? Does the percentage increase as we increase mastery?

[TLTeo 29]

Arcane is a mathematical clusterfuck to model properly. You need really, really complex shit, so really, the answer is "because math says it's optimal".

 

This is a thread from EJ with the math i'm talking about (Markov chains), back when we found out about Arcane's mastery: http://forums.elitistjerks.com/topic/39999-mathematics-of-dynamic-cycles/. Have fun! xD

[Berlinia 168]

Leo is spot on. Arcane is fucked up so simcraft is the only reason we play as we play.

[TLTeo 29]

I'm Teo not Leo. Just saying :P

[Dutchmagoz 30]

A simpler explanation of why:

 

http://altered-time.com/forum/viewtopic.php?f=3&t=972

 

Many popular Arcane Mage guides have the following line in their rotation description:

Cast Arcane Blast, if you are above 93% Mana before your start casting.

The same logic can be found in SimulationCraft's Arcane Mage APL:

arcane_blast,if=buff.arcane_charge.stack=4&mana.pct>93

This has lead to people asking where the 93% "magical number" came from, which I plan to address in this thread.

 

The TL;DR answer is "Using ABar instead of AB at >=93% mana leads to wasted mana". Technically speak, 93% isn't completely on-point, because it's a rounded number. The exact number is actually closer to 92.78% for non Arcane Orb users.

 

Here is a spreadsheet of how an Arcane Mage's mana fluctuates as you dump Arcane Charges and rebuild. As seen in the first section, the highest mana level (highlighted in green) is observed just before you finish casting the second Arcane Blast (AB1, which stands for Arcane Blast with 1 Arcane Charge).

What this means is that if you cast Arcane Barrage at any point above 92.78% mana, you will reach 100% mana when rebuilding Arcane Charges. This means wasted mana. Another way to look at this is any excess mana above 92.78% when casting Arcane Barrage is wasted, because you're already at the highest level of mana possible after rebuilding Arcane Charges.

 

Note that due to Nether Attunement, the spreadsheet applies to all Arcane Mages regardless of haste levels. The numbers are determined by player regen %, base mana costs and the effect of Arcane Charges, not by any character statistic such as haste or mastery.

 

How does Arcane Orb change things? By shortcutting the first 2 Arcane Charges, the player can now stay at a slightly higher mana level before casting Arcane Barrage. But as you see in the spreadsheet, the difference is very small; 93% is still a valid number.

 

The current metagame for Arcane Mage DPS can be interpreted as "Cast as many Arcane Blasts at 4 Arcane Charges as possible". To do this, you want to be efficient with your regen, stay close to maximum mana, while casting the maximum amount on 4 Arcane Charge spells. This is why we avoid mana capping - wasting regen leads to a lower amount of "excess" that can be spent on AB4s.

 

In SimulationCraft, "93%" was chosen not only by spreadsheet analysis, but also through trial-and-error. After experimenting with numbers between 90-95%, it was chosen because it offered the best results.

[TLTeo 29]

Uh that was simpler than i thought

[causevha 1]

So most of the time i have 89-ish% mana when i want to cast AB but I'm not at 93% (or 92,78) before the cast goes through.

I recorded it and it seems that I'm at 92,409-92,484%. Does that mean I should have used arcane barrage when i was at 89-ish% mana? Isn't it more worthy to keep 4 stacks of arcane charge and ignore the 0,38% loss?

Edited January 17, 2015 by causevha