Just echoing the thought so it’s out there on the internet in yet another place.
And no, not melee hit rating. Inner Fire no longer adds attack power. Silly geese.
Spell Hit Rating! The general sentiment you will get for casters looking to increase their dps in raids is thus: get hit capped, then stack spell damage. Yet, I see many casters still ignoring spell hit on gear drops and gemming spell crit. This is not as efficient! By far!
Again, just echoing information you could read in any number of places on the internet, just hoping that having it in yet another spot will allow yet more folks out there to be illuminated.
So, say you have a spell. Let’s assume for now that you have 0% spell crit and 0% additional spell hit. Say that spell hits for exactly 1000 per hit, and we’re going to cast it at a boss 100 times. Assuming no resists, no crits, etc, you will deal 100,000 damage. But, thanks to the resist system, it is not that simple.
A boss is equivalent to a level 73 mob. As such, this boss will have a 16% chance to resist your spells. Completely. Zero damage. A little “Resist” message shoots up instead of a damage number.
So then, let’s factor that in. Over 100 casts, 17% of those (wait, didn’t I say 16%? read more in the next paragraph) will be resisted. 100 casts, 17 resists, 83 hits. 83 x 1000 = 83000. That’s significantly less damage!
Let’s now throw in some talents and intellect-based spell crit chance. Let’s go with an easy 15%. Crits replace hits, so now we have 100 casts: 17 resists, 68 hits, 15 crits.
A little bit on the mechanics of spells first: by default, when a spell crits, it deals one and a half times as much damage. Our 1000 hits will become 1500 crits. (There are talents that change this but we will look at those later.) Also, there appears to be (after much testing by other players) a 1% chance for a mob to resist your spells, no matter how much spell hit you have. So that 16% I mentioned before is actually 17%, but there’s just nothing you can do about that final 1% except maybe grumble loudly. And then I’m not sure what that would do for you, but feel free.
Continuing from there then, 17 resists for 0 damage. 68 hits for 1000 damage each (68,000 total) and 15 crits for 1500 damage each (22,500 total). 90,500 total. Working our way back up there! All right, well. Ignoring talents that increase spell hit for now, and lets take away our spell crit talents as well as they’ve served their purpose for now. Back to 83000 damage total, 17 resists and 83 hits.
All right. On this test caster guy who’s casting some random damage spell hitting for 1000, let’s give him a blank piece of loot, say some pants so he’s not completely naked, and it has but one gem slot. No socket bonus or anything to complicate matters, just a gem slot. And also suppose that Blizzard decided that all gems except the Gleaming Dawnstone (8 spell crit) and Great Dawnstone (8 spell hit) were overpowered. So that’s all we have.
Which one should Mr. or Mrs. Caster use for fighting our boss? Let’s assume a base 1% increased chance to hit and crit, so that we don’t end up critting less than 1% of the time.
At level 70, 12.6 spell hit rating is 1% spell hit. 22.1 (or something close) spell crit rating is 1% spell crit. If we use 8 spell hit, we get 8/12.6 = 0.635% less chance for our spells to be resisted, which would lower it from 16% to 15.365%. (The math will start to get ugly, but bear with me.) If we choose the Gleaming Dawnstone instead for 8 spell crit, we will increase our spell crit chance by 0.362%, from our fabled 1% to 1.362%. Let’s take those numbers and compare!
These are difficult numbers to work with, again. Over 100 casts we will crit 1.362% of the time, which seems silly since it’s a binary system (either you crit or you don’t…there aren’t any fractional crits). But over many successive casts (more than 100, really) this will be how they average out.
| Gem |
Dmg per Cast |
Spell Casts |
Resists |
Hits |
Hit Dmg |
Crits |
Crit Dmg |
Total Dmg |
| Neither |
1000 |
100 |
16 |
83 |
83,000 |
1 |
1500 |
84,500 |
| +8 Spell Hit |
1000 |
100 |
15.365 |
83.635 |
83,635 |
1 |
1500 |
86,135 |
| +8 Spell Crit |
1000 |
100 |
16 |
82.638 |
82,638 |
1.362 |
2043 |
84,681 |
In our example here then, we can see that increasing your spell hit rating by 8 will bring Mr. or Mrs. Caster’s total damage done up to 86,135, while 8 spell crit rating will only bring it to 84,681. That’s a difference of 1454!
Now as I mentioned before though, there are talents in many dps caster trees that will increase the critical strike damage bonus of your spells. Most notably, Ruin, in the Destruction Warlock tree, and Ice Shards, in the Mage Frost tree, will both increase the critical strike damage bonus from a 50% increase to a 100% increase. An obvious increase to the value of spell crit! Will these affect our numbers at all? Let’s find out!
| Gem |
Dmg per Cast |
Spell Casts |
Resists |
Hits |
Hit Dmg |
Crits |
Crit Dmg |
Total Dmg |
| Neither |
1000 |
100 |
16 |
83 |
83,000 |
1 |
2000 |
85,000 |
| +8 Spell Hit |
1000 |
100 |
15.365 |
83.635 |
83,635 |
1 |
2000 |
86,635 |
| +8 Spell Crit |
1000 |
100 |
16 |
82.638 |
82,638 |
1.362 |
2724 |
85,362 |
Spell hit still wins out! 86,635 compared to 85,362. The crit damage increase closed the gap a bit, but did not overcome spell hit in effectiveness.
Now, there are other values to consider in favor of spell crit. Destruction Warlocks, for instance, have a talent called Improved Shadow Bolt that increases shadow damage dealt to the target for a time after a Shadow Bolt crits, from all sources that deal shadow damage. Fire Mages have one called Master of Elements, which refunds some mana when their spells crit, and Ignite, which causes a Damage over Time effect to occur on their target for a percentage of the damage done after a spell critical strike.
However, from a pure damage per second standpoint, spell hit is the winner.
I’ve linked to this post of Coriel’s before, but I continually reference it personally, and would advise others to do the same for additional information! Hit Caps for Bosses.
In short, capping your spell hit at 16% is highly advisable for casters, because of how “cheap” it is (ie, 12.6 rating per 1% hit vs. 22.1 per 1% crit). Those talents you have that increase your chance to hit with spells are very effective at both increasing your DPS and helping you reach that cap. Past 16% though, the stat will not help, as you cannot remove that final 1%, and it will do nothing additional for you. It is at this point that you stack spell damage, for most casters.
Image courtesy of some guy named “Boeotian.” Found the image on imageshack.us.