You can test on a boss if you want but like I said, the damage averages out, especially when using skills like RoF. If 50% of the time you do 100 damage and 50% of the time you do 500 damage, you do 300 damage per hit on average. Instead of you do 400 damage 50% of the time, and 200 damage the other 50%, it still averages to 300 damage per hit. That's basically what the difference between using a ruby or emerald is. After enough hits the average damage is the same. That's more or less the same thing Jaetch just posted, only in different words.
The only exception is Hydra because it only crits for 50% extra damage, regardless of your actual CD.
So really, just use whichever gives the higher dps, or whichever is cheaper to make for you.
That's pretty much what I said in my first post and there isn't really anything else.
I'm gonna have a hard time putting this into words, but weapon% damage already factors into the weapon DPS that you see on the item. So with a ruby or emerald, it doesn't really matter because both will play different roles in boosting your character's DPS depending on all yoir other stats. It'll vary from player to player. At some point or another, they'll offer very similar in benefits (for my wizard I believe it's only approximately 1K difference when unbuffed). But when you're still leveling up, for instance, you have low cc and a ruby is hands down by far the best to use.
I'll reiterate what Loroese said, because I agree. Just look at which one benefits you more in terms of DPS and go with that.
The mention of the weapon damage% is because the ruby damage is modified by that affix, so if you have a 1000-2000 damage weapon without the affix, the weapon becomes 1160 to 2160. If you have 50% weapon damage it instead becomes 1240-2240.
Pretty every weapon used by players who are considering using a Ruby have weapon damage% though, so it's sort of a moot point, but the amount of damage% does impact where the breakeven point is between the two gems.
However if you just compare a 50%weapon dmg ruby (240 avg dmg) with a 110% cd you have to admit that in most cases, if not all, the ruby provides more dps. i played a 230k unbuffed cm wizard with only 250cd and the ruby still was alot better than the emerald.
in the case of my monk (a bit off but whatever) 240avg dmg are 58800 dps. 110cd of the emerald are 36234. thats a difference of 22566 dps. on wizards or other classes the difference might be smaller but still significant. if you are playing a wizard, dh or witchdoc or a barb with a skorn i would suggest if you have 40+% weapon dmg to always use a ruby in your weapon.
If you don't run Deep Freeze, such as group play for Bone Chill or Ubers for Cold Snap, then ruby can beat out emerald at certain higher gear levels. In my old SNS gear I had 245CD before emerald and Marq Em was better for me because I ran Deep Freeze. Without DF a ruby would have been like 560 dps gain. 250 CD means 200 CD on gear besides weapon slot which is actually quite a bit for CMWW, since CD should be the last stat added after AR, armor, IAS, CC.
So for people with that level of gear, Ruby can come out ahead. For those with like 100-200k dps, an Emerald is probably more char sheet dps, but I just tell everyone to use a calculator or spreadsheet to see which is better. For example, with a low damage OH ruby becomes more promising while a high damage OH favors emerald more.
Im pretty astounded noone mentioned that rubys are only good if you have %weapon dmg on your weapon and a decent attackspeed. both increases the effect alot. thats why cm wizards mostly use rubys in their chanto. 1.61-1.65 aps and up to 50% weapon dmg. the base 160 avg dmg of the ruby get thus bumped up to 344 +dps on the weapon whereas if you only had 1.2 aps and no %weapon dmg it only would provide you with 192 avg dmg. thats a huge difference. more to mention is that the ruby does not convert a elemental weapon into a black weapon. %elemental dmg does only work on the ruby. crit chance and crit dmg dont really matter at all. rubys increase the base dmg and thus also the crit dmg.
Attack speed actually has nothing to do with making a ruby better then an emerald. What you're thinking is higher APS weapons have lower average damage, thus ruby adds more average damage. That's true, but that's because of average damage. If you have a 1 APS weapon that is 1000-2000 damage or a 2 APS weapon that is 1000-2000 damage, if a ruby is better in one weapon than an emerald, it will be better in the other weapon, but if an emerald is better in one weapon, it will be better in the other too. You obviously gain more dps from putting a ruby in the 2 APS weapon but you also gain more dps from an emerald in that weapon compared to the first. IAS on gear is the same and impacts both configurations in the same way, as I show above.
Most CM wizards should use an emerald, unless they have very high CD. Otherwise they'll get more dps out of an emerald, especially those running Deep Freeze, since it gives 15% extra crit and has a very high uptime thanks to mob density.
As for the weapon damage%, it's implied to be present when the OP said both gems give about the same char sheet dps. OP also has a Skorn in profile which has the weapon damage%, otherwise a ruby likely wouldn't even be worth consideration.
I could go into more detail about what stats lead to ruby or emerald giving higher char sheet dps but that's a bit off topic. I stand by my previous statement that the best option is to just use whichever gives the higher char sheet dps, UNLESS you're using Hydra. That's the only wizard skill that doesn't scale from crit damage.
I'm saying the elemental damage adds the same bonus dps multiplier regardless of if you use a ruby or emerald. That's only true when you have a black weapon. So when trying to figure out which gives you more dps the elemental damage doesn't matter.
The simplified DPS formula becomes
DPS = (ave weapon damage)*(Weapon APS)*(1+sum(IAS))*(1+CC*CD)*(1+Elemental Damage)*(1+Int/1000)
The factors of Weapon APS, 1+sum(IAS), 1+Elemental Damage, 1+int/1000 are the same for both gems with a black weapon. In that case the ruby directly adds to the ave weapon damage and the emerald adds directly to CD. In other words, if you have the same dps with a ruby as an emerald but add 1% extra elemental damage while keeping everything else the same, then you'll still get the same dps from ruby or emerald.
Probably Jaetch or Loroese will be able to help the best.
I know Jaetch opts for Ruby.
It may depend on your build. I heard something about Rubys being better with Archons disentigration wave.. not totally sure.
It could also be that the +%elemental damage is the key for the switch. So if you have a really high total +%elemental damage then socketing your Blackweapon with a Ruby increases its effect/your dps a lot more.
When using a black weapon the +%elemental damage doesn't matter. It only plays a role in determining which is better if you have a non-black weapon.
For Archon beam or other similar spells, it's just best to use whichever gives the most char sheet dps because the beam hits like 30-60 times per second, so the damage averages out pretty well either way.
If you're using a blizzard build, it might be more beneficial to use a ruby for the more consistant damage but in the end the damage should average out well enough, especially for the channeled spell (RoF). In the end I'd just use whichever gives more dps or whichever you actually have made at the time (or whichever is cheaper since the damage is so close).
Really the only time it might make a difference is if you use Hydra, since hydra doesn't scale with Crit damage.
The only exception is Hydra because it only crits for 50% extra damage, regardless of your actual CD.
So really, just use whichever gives the higher dps, or whichever is cheaper to make for you.
That's pretty much what I said in my first post and there isn't really anything else.
Crusader DPS and EHP Spreadsheet, meant for Crusaders
My Wizard
The mention of the weapon damage% is because the ruby damage is modified by that affix, so if you have a 1000-2000 damage weapon without the affix, the weapon becomes 1160 to 2160. If you have 50% weapon damage it instead becomes 1240-2240.
Pretty every weapon used by players who are considering using a Ruby have weapon damage% though, so it's sort of a moot point, but the amount of damage% does impact where the breakeven point is between the two gems.
Crusader DPS and EHP Spreadsheet, meant for Crusaders
My Wizard
If you don't run Deep Freeze, such as group play for Bone Chill or Ubers for Cold Snap, then ruby can beat out emerald at certain higher gear levels. In my old SNS gear I had 245CD before emerald and Marq Em was better for me because I ran Deep Freeze. Without DF a ruby would have been like 560 dps gain. 250 CD means 200 CD on gear besides weapon slot which is actually quite a bit for CMWW, since CD should be the last stat added after AR, armor, IAS, CC.
So for people with that level of gear, Ruby can come out ahead. For those with like 100-200k dps, an Emerald is probably more char sheet dps, but I just tell everyone to use a calculator or spreadsheet to see which is better. For example, with a low damage OH ruby becomes more promising while a high damage OH favors emerald more.
Crusader DPS and EHP Spreadsheet, meant for Crusaders
My Wizard
Attack speed actually has nothing to do with making a ruby better then an emerald. What you're thinking is higher APS weapons have lower average damage, thus ruby adds more average damage. That's true, but that's because of average damage. If you have a 1 APS weapon that is 1000-2000 damage or a 2 APS weapon that is 1000-2000 damage, if a ruby is better in one weapon than an emerald, it will be better in the other weapon, but if an emerald is better in one weapon, it will be better in the other too. You obviously gain more dps from putting a ruby in the 2 APS weapon but you also gain more dps from an emerald in that weapon compared to the first. IAS on gear is the same and impacts both configurations in the same way, as I show above.
Most CM wizards should use an emerald, unless they have very high CD. Otherwise they'll get more dps out of an emerald, especially those running Deep Freeze, since it gives 15% extra crit and has a very high uptime thanks to mob density.
As for the weapon damage%, it's implied to be present when the OP said both gems give about the same char sheet dps. OP also has a Skorn in profile which has the weapon damage%, otherwise a ruby likely wouldn't even be worth consideration.
I could go into more detail about what stats lead to ruby or emerald giving higher char sheet dps but that's a bit off topic. I stand by my previous statement that the best option is to just use whichever gives the higher char sheet dps, UNLESS you're using Hydra. That's the only wizard skill that doesn't scale from crit damage.
Crusader DPS and EHP Spreadsheet, meant for Crusaders
My Wizard
The simplified DPS formula becomes
DPS = (ave weapon damage)*(Weapon APS)*(1+sum(IAS))*(1+CC*CD)*(1+Elemental Damage)*(1+Int/1000)
The factors of Weapon APS, 1+sum(IAS), 1+Elemental Damage, 1+int/1000 are the same for both gems with a black weapon. In that case the ruby directly adds to the ave weapon damage and the emerald adds directly to CD. In other words, if you have the same dps with a ruby as an emerald but add 1% extra elemental damage while keeping everything else the same, then you'll still get the same dps from ruby or emerald.
Crusader DPS and EHP Spreadsheet, meant for Crusaders
My Wizard
When using a black weapon the +%elemental damage doesn't matter. It only plays a role in determining which is better if you have a non-black weapon.
For Archon beam or other similar spells, it's just best to use whichever gives the most char sheet dps because the beam hits like 30-60 times per second, so the damage averages out pretty well either way.
Crusader DPS and EHP Spreadsheet, meant for Crusaders
My Wizard
This you?
If you're using a blizzard build, it might be more beneficial to use a ruby for the more consistant damage but in the end the damage should average out well enough, especially for the channeled spell (RoF). In the end I'd just use whichever gives more dps or whichever you actually have made at the time (or whichever is cheaper since the damage is so close).
Really the only time it might make a difference is if you use Hydra, since hydra doesn't scale with Crit damage.
Crusader DPS and EHP Spreadsheet, meant for Crusaders
My Wizard