This question has been asked in the Warlock's Den forums over and over, and the answer is generally:

But why? Is there anything special about 25%?

I used a spreadhseet model to have a look at the damage contribution of two key Shadow Bolt (SB) talents, Improved Shadow Bolt and Ruin, at various levels of spell crit in a previous blog entry. The results were not cut and dried, so I'm trying a different approach. There's a lot more difference between an afflock and a destrolock that having Ruin on the talent list. The affliction does about half of his or her damage with DoTs, which don't crit, and can do more damage than an SB-spamming destrolock at low levels of spell crit. So I took my previous Shadow Bolt model, pulled together a DoT model, and worked out the effects of two different talent trees. I'm assuming a typical spreadsheet fight, with infinite mana, no damage/silence/movement/distractions and DoTs that somehow manage not to expire together. I'm also assuming each is the only shadow caster in his/her raid. I'm not including immolate; it's a lot of work to add to a model, and it has little effect on the DPS of these types of warlocks.

Both builds were assumed to have:

• +1100 shadow damage from gear and buffs
• Fel Armor
• 5/5 Improved Shadow Bolt
• 5/5 Bane
• 100% spell hit
• Curse of Recklessness duty

The afflock has:

• full Improved and Empowered Corruption
• Contagion
• Siphon Life
• 5/5 Shadow Mastery
• 5/5 Contagion
• Unstable Affliction

The destrolock has:

• Ruin
• Shadow and Flame
• Demonic Sacrifice and a sacrificed succubus
• Improved Demonic Aegis (Oh, boy, +30 spell damage)

With this model, the destrolock starts doing more DPS than the afflock after 12% spell crit. However, small differences in DPS are hard to notice and will be washed out by differences in playstyle: are you a highly mobile caster? Are you good at keeping an eye on your DoTimer? Do your DoTs tend to expire all at the same time? At 25%, assuming limited-mobility fights and good raid healing, destro will be doing as much as 91 DPS more, and the improvement should be very noticeable.

The destrolock would obviously have 5/5 Devastation (as do many afflocks) and 3/3 Backlash, but I didn't split those out, because I really want a good look at the effect of spell crit. One reason that warlocks may notice a big change in DPS when they respec if they wait until they have 20% spell crit from gear and their basic raiding talents is that they gain 3% to 8% crit from the respec alone.

However, I noticed while using Tears of the Goddess (a slow-fall doohickey for the Archimonde event) that my WoW game lags slightly, probably for a variety of reasons. My latency is generally pretty good: 200-250 ms. But it varies and can get worse in a raid setting. So I checked to see if the model were sensitive to lag by adding 1 second (1000 ms; my connection is rarely that bad in a raid) to the cast time of every spell.



Unsurprisingly, lag is bad for warlock DPS. It's worse for destro than affliction and reduces the contribution of spell crit chance to DPS. If your server/computer/connection lag severely, stay affliction rather than switching to destro until you have quite a bit more than 25% crit for SBs.



Blood Pact: Destro the only way to go?