Simcraft Supplemental: Socket Bonus or Socket Spellpower?

One of the most important reasons to use simcraft is to find your scale factors, which will determine your best course of gearing, gemming, and enchanting. Today, we're going to discuss gemming. For our example, I'm going to show off the new robe I won the other day, the heroic Flowing Sanctum Vestments

This makes a good example piece - three gem slots, a good socket bonus, and no particularly fiddly stats like hit.

First thing's first, you'll want to use simcraft to get your scaling factors. Mine, for destruction:
Spellpower: 1.58
Haste: 0.94
Crit: 0.71
Spirit: 0.71
Int: 0.62


Now, it's easy to see why spellpower is a strong stat - it has the highest scaling factor, and costs less itemization, so spellpower gems have 23 spellpower, compared to 20 of most other stats. When hitting a blue or yellow socket, it's best to use a split gem with spellpower, to reduce the opportunity cost of that socket.

What gem per socket? Red is easy - spellpower. We've already discussed why it's the one stat to rule all others.

Blue sockets are also easy, blue being such a sparse socket color with only four stats. MP5 isn't a viable DPS stat, stamina contributes no DPS to most builds and a trivial amount to demonology, and spell penetration doesn't have any effect against PVE targets. Spirit is our only option, but it's a strong DPS stat for all of our builds. My simcraft parse above was done without glyph of life tap, and even then, it's equal to crit rating. With glyph of life tap, it can potentially be your second strongest DPS stat after spellpower itself.

Available stats for yellow sockets are intellect, haste, and crit. Intellect can be tossed aside immediately, only improved soul leech builds that don't use glyph of life tap will have a significant scale factor from intellect, and it'll still be by a good margin the worst DPS stat. You want to go with the one that's your highest scale factor, which in my case is haste. Destruction and demonology builds will almost always have higher scale factors for haste than crit. Affliction, however, isn't always so simple.

Let's take a look at the 3.2.2 tier 9 affliction best in slot profile. It's scale factors for crit and haste are 1.03 and 0.95, respectively. Wait, what's this? Yep - crit, not haste. Affliction doesn't scale particularly well with haste OR crit currently, since it has a good deal of damage that isn't effected by haste. Now, this isn't really a big consideration for affliciton, since both stats are fairly weak, it's less likely to bother with set bonuses.

So, on to the part you care about!

We've got our scale factors, and we know our best gem selections for each color. Our robe has one socket of each color, and a socket bonus of 9 spellpower - quite good as bonuses go.

Case 1: Straight Spellpower
23 spellpower x3=69 spellpower
69 spellpower x1.58=109.02 dps

This is the bog standard boring bonuses be damned for spellpower. And it's pretty good.

Case 2: Socket Bonus
 Red socket: 23 spellpower
Yellow socket: 12 spellpower, 10 haste
Blue socket: 12 spellpower, 10 spirit
Bonus: 9 spellpower

Totals: 56 spellpower, 10 spirit, 10 haste
56 spellpower x1.58=88.48 dps
10 spirit x0.71=7.1 dps
10 haste x0.94=9.4 dps
Total: 104.98 dps

As you can see, it's a net loss here, BUT, it's a small one. Somebody with better gear, meaning a higher haste scale factor, and the glyph of life tap may just have what it takes to make up the last 5 dps.

Case 3: You need the Blue Socket Anyway
As you know, your Chaotic Skyflare Diamond requires you to have two blue gems to activate anyway. What if one of them is in your robe? Doing this with straight spellpower yields this:


Blue socket: 12 spellpower, 10 spirit
23 spellpower x2=46 spellpower

Totals: 58 spellpower, 10 spirit
58 spellpower x1.58=91.64 dps
10 spirit x0.71=7.1 dps
Total: 98.74 dps

Which is actually a bigger loss than getting the socket bonus, so you're better off finishing the socket out to get some spellpower back. However, there may be better places to use those gems, look for items in your gear with just a blue socket (like the tier 9.245 helm, which has only a blue socket and also give a 9 spellpower bonus), or an item with a red/blue pairing, which also means no additional tradeoff to get the bonus.

So, how does this effect you?

I prefer to do this process on a per-item basis. I get a new item, I play with the options for it and find the best gain for myself. Occasionally I reevaluate items with good bonuses, like the tier 9.245 pants, which have a red/yellow socket pair and a 7 spellpower bonus. You can take this so far as to test your entire configuration every time you change something, find the optimal place for your required blue gems, find the optimal set of socket bonuses and straight spellpower, etc. It can get expensive, but it's an option. As you can see above, we are talking about differences of as little as 5 DPS, you may honestly just prefer to get socket bonuses just because, and it won't hurt you terribly, provided you do it right.

Just remember, if you're going to try to min/max down to this level, don't just take the scale factors off of ElitistJerks, or even on this blog. Use simcraft, get accurate and current figures for your own gear. Your scale factors aren't the same as mine, and unless you happen to have the absolute best in slot gear, they're not the same as the ones posted on EJ. Scale factors are not constants to be used in a vacuum. They will change with your gear, spec, and glyphs - everything that changes your character will potentially change your scale factors.