Drain Life vs Shadow Bolt

Overview

This is something that has bugged me for a while. There are a lot of Warlock raiders out there who completely fail to understand how Drain Life and Shadow Bolt work and, as a result, which is better. It's mostly Affliction Locks who make this mistake and I can understand why a new Affliction raider can make that mistake. There are Affliction talents that make Drain Life better and it helps keep your HP up when you use Life Tap, not to mention Suppression which improves spell hit rating on Affliction spells. Shadow Bolt is a Destruction talent, so I, as an Affliction Lock, do not need to focus on Shadow Bolt. But it's not just the newbie raiders out there who are making this inaccurate assumption, there are also those who should know better who are making this same mistake. So hopefully, once and for all, I am going to show exactly what is going on.

Shadow Bolt is ALWAYS better than Drain Life!

It really is that simple. Except in a very few select situations, during raiding, Shadow Bolt is always the better choice than Drain Life. No matter how much you improve Drain Life talents and no matter how much you neglect Shadow Bolt talents, Shadow Bolt is better. It does not matter what spec you are. It does not matter what your level of gear is. Shadow Bolt will always provide more DPS.

The reason that Shadow Bolt is so much better to use over Drain Life, even as an Affliction Lock, is because Shadow Bolt is the primary DPS spell available for Warlocks. It does high base damage. It also has a chance to crit, unlike Drain Life. In addition, Shadow Bolt scales considerably better with gear than a DoT like Drain Life does. So as you get more and better gear, Shadow Bolt improves DPS more over Drain Life.

Another just as important reason why Shadow Bolt is better is because of Improved Shadow Bolt (ISB). ISB increases shadow damage raid-wide by 20% whenever a Shadow Bolt crits. Therefore, 5/5 in ISB and 5/5 in Bane are considered essential must-have talents in ANY raid build. While Affliction Locks will have less crit and spend less time casting Shadow Bolts, the little bit they can contribute to ISB uptime is still significant. Therefore Affliction Locks are wrong to assume that they don't need to worry about Shadow Bolts. They absolutely should be casting Shadow Bolts between DOTs.

Drain Life also takes longer to channel than Shadow Bolt, esp with the Bane talent. Drain Life is 5 seconds for a full cast compared to a 2.5 Shadow Bolt with Bane. So you can get two Shadow Bolts out during that Drain Life instead. Many fights are mobile and require you to run around a lot. Affliction is nice in that you can cast a lot of DOTs on the run. So why would you then do the opposite and cast a longer casting spell between DOTs?

But what is all this without some theorycrafting to back up my claims? Well that is exactly what I am going to do. First, let me lay down my hypothesis, assumptions, and general plan of action.

Hypothesis: There is no combination of talent build and gear that makes Drain Life do more DPS than Shadow Bolt.

Assumptions: Testing against single target raid bosses. Max-DPS rotations and curse selection will be used. Stand still tank-and-spank situation where no movement is required. Improved 3/3 Curse of Shadow is kept up by someone else. This creates the ideal environment where we can focus solely on how much DPS is gained or lost when switching Shadow Bolt with Drain Life. For simplicity, I am just going to assume +shadow and +fire are the same. Most Locks will have more +shadow, but this won't taint the results at all since it only affects Immolate, which will remain static between trials of each test. I am also ignoring haste for the time being, since beginning Locks will not have much access to it anyway, Affliction Locks don't value it as much, and the mechanics of haste are being changed in the near future.

Testing Plan: Using the Warlock DPS spreadsheet, I will test the DPS results of the main Affliction raid builds using Shadow Bolt and Drain Life. I will test different levels of gear as well as different, unorthodox, spell rotations. I will even test what happens when the Lock is grouped with different classes (Shadow Priest, Moonkin, and Shaman.) Finally, I will then start to play around and try anything possible to make Drain Life out-DPS Shadow Bolt, if possible.

Theorycrafting

Format I will use:
Test: Description of what is being tested
Spec: Link to spec being used
Filler Spell: Which spell between Drain Life and Shadow Bolt is being used between DOTs
Dmg: Amount of spell damage
Spell hit: Spell hit rating from gear only
Crit: Spell crit rating
HP: Health
Mana: Mana
Spell Rotation: What spells are being used
DPS: resulting Damage Per Second time (higher is better.)
OOM Time: Out of Mana Time (higher is better)
Net DPS: DPS gained (or lost) by using Drain Life instead of Shadow Bolt.
Comments: Comments on the results found

Round 1

Test: General early T5 Affliction raid spec and gear. Spell hit capped without suppression. In tank group with Imp out. Dark Pact and Health Tap are used when needed.
Spec: 44/0/17

Filler Spell: Shadow Bolt
Dmg: 1000
Spell hit: 16%
Crit: 20%
HP: 10000
Mana: 10000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Shadow Bolt, refresh DOT's as needed
DPS: 1217.45
OOM Time: -

Filler Spell: Drain Life
Dmg: 1000
Spell hit: 16%
Crit: 20%
HP: 10000
Mana: 10000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Shadow Bolt, refresh DOT's as needed
DPS: 1119.81
OOM Time: -

Net DPS: -97.64
Comments: This is the overall best Affliction based spec covering all the necessities while maximizing individual DPS potential. Note that in this spec, Locks have unlimited mana. The result is a nearly 100 loss in DPS. This is in effect over a long fight. What about if the fight is very short, or if there is a shorter "burst" phase?

Test: Using the same exact spec and gear as above, only difference is that max DPS is needed and Dark Pact and Life Tap is not allowed. Chugging mana pots is used instead.

Filler Spell: Shadow Bolt
DPS: 1346.46
OOM Time: 61 s

Filler Spell: Drain Life
DPS: 1186.38
OOM Time: 82 s

Net DPS: -160.08
Comments: As we can see, there is an even greater loss in DPS during a straight max-DPS burst. This is very conclusive that Shadow Bolt does more DPS and is therefore a better filler between DOTs. However, using Drain Life does allow the Lock to last longer before going out of mana by 21 seconds. Does this make a difference? Let's find out.

1346.46 DPS x 61 s = 82134.06 total damage output
1186.38 DPS x 82 s = 97283.16 total damage output

What this tells us is that by using Drain Life, the Warlock will last longer, thus allowing more time for DOTs to tick, resulting in more overall damage done before running out of mana. This is an extremely unrealistic scenario though. Locks are going to be able to Life Tap at least some of the time and likely to get some heals here and there. Thus it is far more important (and realistic) to focus on the DPS and ignore the OOM Time. Obviously you can last longer by using Drain Life, but most encounters have timers that you have to beat, thus it is stupid to think that it is better to use Drain Life just because you can do more damage EVENTUALLY given the time. The fact is, you don't have that time. You need to do that damage now.

Round 2

Test: General Affliction spec, only with less spell hit and relying on suppression to reach hit cap. Normal Life Tap and Dark Pact use are allowed.
Spec: 44/0/17 with Suppression

Filler Spell: Shadow Bolt
Dmg: 1000
Spell hit: 6%
Crit: 20%
HP: 10000
Mana: 10000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Shadow Bolt, refresh DOT's as needed
DPS: 1148.88
OOM Time: -

Filler Spell: Drain Life
Dmg: 1000
Spell hit: 6%
Crit: 20%
HP: 10000
Mana: 10000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Shadow Bolt, refresh DOT's as needed
DPS: 1093.24
OOM Time: -

Net DPS: -58.98
Comments: The point of this test is that since a lot of Affliction Locks are just starting out and do not have enough spell hit from gear (or worse, refuse to put spell hit on gear) and rely on Suppression to make up the difference, they think that Shadow Bolt will miss too often to be worth it. This has just been proven wrong as even with the extra misses, Shadow Bolt still gave a higher DPS. Notice that the overall DPS lowered in both trials from the first test. This is because Immolate is not affected by Suppression. What happens if we take Immolate out of the rotation and use Drain Life over Shadow Bolt, ensuring that all spells cast are Affliction, and thus you are effectively hit capped the entire rotation?

Test: Same as above, minus Immolate and Shadow Bolt
DPS: 1048.57

Net DPS (from previous Drain Life trial with Immolate): -55.57
Comments: Huh, lost DPS there. Immolate is a good spell and has a higher damage per cast time than Shadow Bolt. Until you have a lot more shadow damage than fire, Immolate is worth casting.

Round 3

Test: Alternative Affliction/Demonology spec that supposedly boosts Drain Life. Normal Dark Pact and Life Tap use are allowed. Gear will be consistent with the previous tests. Not hit capped from gear, suppression used. NOTE: I am using the same numbers except for +crit as with the previous specs. This is because the extra stamina and intellect gained from these talents have almost no effect whatsoever on DPS, however Crit does have a significant effect. Thus this is easier and just as accurate for the purpose of this particular test.
Spec: 44/17/0

Filler Spell: Shadow Bolt
Dmg: 1000
Spell hit: 6%
Crit: 15%
HP: 10000
Mana: 10000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Shadow Bolt, refresh DOT's as needed
DPS: 996.69
OOM Time: -

Filler Spell: Drain Life
Dmg: 1000
Spell hit: 6%
Crit: 15%
HP: 10000
Mana: 10000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Shadow Bolt, refresh DOT's as needed
DPS: 1008.94
OOM Time: -

Net DPS: 12.25
Comments: Ok, I have to admit that I was surprised with this result. I knew it would be close, but I assumed Shadow Bolt would still come out slightly on top. The reason Drain Life is closer (or in this case superior) to Shadow Bolt with this spec is not so much that you improved Drain Life enough to make it effective, as much as you gimped and neglected Shadow Bolt so much that Drain Life became effective. Look at the overall DPS compared to the 44/0/17 specs.

Both with 6% spell hit and Suppression
44/0/17 Shadow Bolt: 1148.88
44/17/0 Drain Life: 1008.94
Net DPS (of 44/17/0 Drain Life spec): -139.94

With 44/17/0, your Shadow Bolts have longer casting time and you have lower crit. Using Drain Life with this spec is superior because the Sbolts take so long to cast that it's better to use Drain Life and hope for some Nightfall procs. But overall, the same exact gear using 44/0/17 and Shadow Bolt will gain 140 DPS simply from moving those 17 points around. Not only that, but you also contribute to ISB uptime and will increase overall raid DPS more with 44/0/17.

Round 4 - Comparing differences in Net DPS at different gear levels with 44/17/0

Test: Not spell hit capped and using Suppression. Higher quality gear results in higher shadow damage and crit.
Spec: 44/17/0

Filler Spell: Shadow Bolt
Dmg: 2000
Spell hit: 6%
Crit: 25%
HP: 12000
Mana: 12000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Shadow Bolt, refresh DOT's as needed
DPS: 1599.41

Filler Spell: Drain Life
Dmg: 2000
Spell hit: 6%
Crit: 25%
HP: 12000
Mana: 12000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Shadow Bolt, refresh DOT's as needed
DPS: 1583.82

Net DPS: -16.59
Comments: This test shows how Shadow Bolt scales better with damage than DOTs (which Drain Life counts as.) By getting much better gear, Shadow Bolt has improved more than Drain Life has. With this same spec before, Drain Life came out on top by 12, but now it is behind by 16.5. Of course with this level of gear you would likely find it impossible to not reach the hit cap from gear so let's add that in.

Test: Same as above, but with being spell hit capped from gear.
Spec: 44/17/0

Filler Spell: Shadow Bolt
Dmg: 2000
Spell hit: 16%
Crit: 25%
HP: 12000
Mana: 12000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Shadow Bolt, refresh DOT's as needed
DPS: 1669.80

Filler Spell: Drain Life
Dmg: 2000
Spell hit: 16%
Crit: 25%
HP: 12000
Mana: 12000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Shadow Bolt, refresh DOT's as needed
DPS: 1606.49

Net DPS: -63.31
Comments: Shadow Bolt clearly comes out ahead when adding the spell hit that you would probably have at this gear level. Of course this spec has already been shown to gimp your DPS potential, so how would this spec, using Drain Life, compare with the better Affliction spec, using Shadow Bolt at this gear level?

44/17/0 Drain Life: 1606.04
44/0/17 Shadow Bolt: 1980.87
Net DPS (of using 44/17/0): -374.83
Comments: Wow! That is rather conclusive I would say. This round of tests perfectly illustrates that Shadow Bolt scales way better to addition shadow damage than Drain Life. This is at extremely high gear levels of course but it clearly shows the concept

Round 5 - Comparing very low level gear

Test: Very low gear, barely any spell hit
Spec: 44/17/0
Filler Spell: Drain Life
Dmg: 500
Spell hit: 2%
Crit: 2%
HP: 7000
Mana: 6000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Drain Life, refresh DOT's as needed
DPS: 710.01

Spec: 44/0/17
Filler Spell: Shadow Bolt
Dmg: 500
Spell hit: 2%
Crit: 2%
HP: 7000
Mana: 6000
Spell Rotation: Curse of Doom, Unstable Affliction, Corruption, Siphon Life, Immolate, Shadow Bolt, refresh DOT's as needed
DPS: 767.17

Net DPS: -57.16
Comments: Even at very low gear levels, probably equivalent to just hitting 70 and not having done any runs for gear yet, the 44/17/0 Drain Life build is subpar.

Conclusions

As was expected, Shadow Bolt comes out on top over Drain Life, by a lot in many cases. Shadow Bolt scales better with damage, benefits from crit and haste, and contributes to ISB uptime. Furthermore, 44/0/17 has been shown to boost DPS over 44/17/0. In fact, the only possible way to make Drain Life out DPS Shadow Bolt is simply to use an obviously subpar build and neglect spell hit rating enough that Shadow Bolt is gimped so much that Drain Life suddenly seems better. It actually isn't! The entire spec is doing lower DPS because it severely neglects and ignores the most fundamental and important damage spell a Warlock has - Shadow Bolt. That would be comparable to saying you are faster than someone driving a car, when you took out the car engine and the other person had to push the car.

44/17/0 and Drain Life are not raid worthy at all. It may be nice for solo or maybe PVP where you are regularly taking damage and are your sole healer. But in a raid setting, it is clearly inferior to other specs. The only time you would use this as a serious raid spec is if you had very low gear and were afraid of dying easily. In that case you shouldn't even be allowed to raid to begin with. Spend a few weeks in Kara and Heroics and gear up a bit.

Also note that this is ideal DPS situations and in game results will vary considerably. There is a lot of running around needed in a real raid. You will be taking some damage here and there, sometimes a lot. Actual DPS will be lower. However the point of this project was simply to show that Shadow Bolt is better than Drain Life, even as Affliction. I think this did an accurate job of proving just that.

About half of an Affliction Locks DPS should come from Destruction via Shadow Bolt and Immolate. Therefore it is also important to still work towards getting spell hit capped from gear rather than relying on suppression.

PS. I think I original said that I would show some tests on grouping with certain classes but didn't get around to it. There really shouldn't be much to test that wasn't already. Any group buff that increases crit or haste will benefit Shadow Bolt and not Drain Life. Any general damage buff will benefit either, but since Shadow Bolt already has a higher base DPS, any additional damage buff will therefore mean that Shadow Bolt still have higher base DPS. However the fact that SBolt can crit means that you actually get slightly more out of that additional damage buff with SBolt over Drain Life due to increasing the damage potential of the crits.