Arcane Mages: When to start the burn phase

One of the biggest questions for Arcane Mages in Legion is… When should I start my burn phase?

How long it takes for an Arcane Mage to burn through their mana varies quite a bit – it’s never the same from one burn phase to the next, which is why this has been such a difficult question to answer. But we’ve solved it by asking Mr. Robot to learn how long each burn phase lasts in every simulation. Then he reports the shortest, longest, and average durations in the report so we can start to answer this difficult question.

After a lot of testing, a pattern emerged. The duration of your burn phase depends on your Mastery:Haste ratios, which appears to hold true at any gear level (during tests with Quickening). It’s important to note that these are initial findings and things might change as we do more testing.

Test your own setup in the simulator.

Before I explain how we came to this conclusion…

Let’s quickly review the burn / conserve phase situation

Here’s the super simple rundown: One of the main Arcane Mage spells is Arcane Blast. Every time you cast it, you get 1 Arcane Charge (which stacks up to 4 times). Arcane Charge increases the damage you do, but it also increases the amount of mana that Arcane Blast costs. Which of course means that you can run out of mana really fast if you keep spamming Arcane Blast. So you need to dump your Arcane Charges with Arcane Barrage to avoid running out of mana. That’s what people refer to as the “Conserve Phase” – you build up to 4 Arcane Charges and then dump them with Arcane Barrage, thus conserving mana until you are ready to “burn.”

This is where Evocation comes in to play. It gives back all of your mana. The strategy for max damage is to stop using Arcane Barrage and “burn” all of your mana by spamming 4 charge Arcane Blasts once you know Evocation will be ready when you run out of mana. So the trick is to time up running out of mana from your “burn” with Evocation coming off cooldown.

The burn phase is dependent on 2 major factors: your gear (mainly Haste and Mastery) and the number of Arcane Missile procs you get during burn. The reason that matters is they cost no mana and allow passive regen during their channel time.

Estimating the length of your burn phase is difficult and this is where robots save the day!

Testing the burn phase duration

I mentioned that we asked Mr. Robot to track the burn phase durations. We do this with a “Learned Value.” Basically, you can ask Mr. Robot to keep an eye on something specific and he learns the pattern over tens of thousands of simulations.

So we asked him to learn how long the burn phase lasts. We simulated this over different gear levels with different stat configurations. I held the talents constant for these initial tests (using Quickening and not Word of Power).

The results lead us to our “Ah ha!” moment when the pattern emerged: the burn phase duration is mostly dependent on the relationship between Mastery and Haste. I suppose that isn’t too surprising, since Mastery gives you mana and Haste spends it faster. And this holds true across the different gear levels.

But here’s the big fat early theorycraft warning, that these might change. Blizzard might change things or maybe we find a bug (GASP!!) in the simulator that changes things. We’ve been over the Arcane model about half a dozen times now, looking for bugs, and thanks to the help of Binkenstein’s independent testing, he found a couple of the last lingering bugs, and it looks pretty bug-free right now (but that doesn’t mean there isn’t another one or two hiding!)

Burn phase results

We then took this “learned value” and used it in the rotation to find out when the best time is to start the burn phase.

We tested starting the burn phase at the shortest duration, to be very conservative so that we never run out of mana before Evocation comes off cooldown. We then tested it with an aggressive strategy, using the average burn duration, which means that some of the time we’ll run out of mana well before Evocation comes off cooldown. We also tried timing it up with Arcane Power. After even more tinkering, we found that starting your burn phase half way between the shortest and average got the highest DPS.

Burn phase “start time” tests with balanced stats & 840 iLevel:

Start burn at shortest duration (conservative): 213,533 DPS
Start burn at average duration (aggressive): 212, 987 DPS
Time up burn phase with Arcane Power: 210,778 DPS
Start burn half way between (slightly conservative): 215,955 DPS

Does this REALLY work with low and high gear levels?

It does! In fact, that’s how I caught the pattern in the first place… when I realized that every gear level test was yielding the same results.

I tested this with the “half way between” burn phase start-time, across different levels of gear, varying the amount of Mastery and Haste. I held talents, trinkets, and everything else constant. Here are the results (with about a 100 DPS margin of error):

840 Gear

Mastery 24.7% / Haste 14.5% 215,955 DPS, start burn at 24 seconds
Mastery 21.9% / Haste 17.6% 216,550 DPS, start burn at 26 seconds
Mastery 19% / Haste 20.7% 216,040 DPS, start burn at 28 seconds
Mastery 27.6% / Haste 11.5% 215,718 DPS, start burn at 30 seconds
Mastery 30.5% / Haste 8.4% 215,661 DPS, start burn at 32 seconds

855 Gear (some Normal, some Heroic gear)

Mastery 20.7% / Haste 21.8% 234,394 DPS, start burn at 24 seconds
Mastery 23.6% / Haste 18.8% 235,015 DPS, start burn at 26 seconds
Mastery 26.4% / Haste 15.7% 234,649 DPS, start burn at 28 seconds
Mastery 29.3% / Haste 12.6% 233,756 DPS, start burn at 29.5 seconds
Mastery 32.1% / Haste 9.5% 233,604 DPS, start burn at 31 seconds

872 Gear (some Heroic, some Mythic)

Mastery 22% / Haste 23.3% 254,505 DPS, start burn at 24 seconds
Mastery 24.9% / Haste 20.3% 254,991 DPS, start burn at 25.5 seconds
Mastery 27.8% / Haste 17.2% 254,877 DPS, start burn at 27.5 seconds
Mastery 30.6% / Haste 14.1% 254,341 DPS, start burn at 29 seconds
Mastery 33.5% / Haste 11% 254,059 DPS, start burn at 31.5 seconds

Learn how long your own burn phase lasts – it’s easy!

Since the burn phase is dependent on gear and talents, it’s helpful to get the value for your specific setup.

We built this into the default rotation so you can play with it.

Load our 840 default mage profile (or any gear set I’ve made, by clicking the Sim this character link from any report that I’ve linked). You can change any of the gear, artifact traits, or relics super easily (here’s a 60 second video to demonstrate just how easy it is).
Choose the default rotation when you setup a simulation (it’s on the right side, 3rd drop down box).
Click Simulate.
Expand the “Rotation” section of the report (see below) and look at the ‘learned values’ section. Initial tests show that you want to be half way between the average and minimum for the burn phase.

Get fancy & edit the rotation yourself!

You can try out the different tests we’ve done by enabling or disabling the different setups we put into the rotation. To do that, click on this shared rotation. Click the copy button at the top and give it a new name. Then click the edit button. Disable and enable different “switches” labeled “Burn Phase” with the blue “SW” box next to them. It’s similar to the Roll the Bones tests we setup for rogues, so this video might be helpful… I’ve queued it up to the relevant part.

If you’re new to our simulator, here’s some helpful resources:

The actual simulator
9 minute crash course that covers the basics
5 minute “deep dive” into rotation editing (it’s really easy actually)
Our documentation page
Full list of video and blog resources

Setting up your own Learned Values

I don’t have a tutorial ready for this, but it’s coming soon. For the adventurous person, you can play with it without a tutorial (crazy!) in the rotation editor. If you look just above the action lists, you’ll see “Learned Values” listed in blue. Click the arrow to expand it and you can add values that you want.