Bow: 20/20 vs Vamp in HM?

For bows; i know that 20/20 and vamp is pretty par, but wouldn't vamp be to prefer in HM?

I'd think vampiric is better. I went through legendary vanquisher and guardian with sundering.

I'd go with vamp. as well, since the extra damage is armor ignoring. The higher AL of enemies in HM reduces the effectivness of sundering mods.

Vamp is consistently better, the base damage range of bows isn't that great anyway so sundering mods are sucky. But, like you've said, this is only for optimising your attacks, bows aren't great in HM for plain damage.

Vamp mods produce more damage, so that's the optimal choice unless you need to use a different string (like a zealous, for example). It's also worth noting that sundering helps you less as the AL of the foe increases. It's true that you cut through more armor, but you still don't make up enough damage to surpass vamp. From my Warrior guide:

Referring to sword numbers here, though the principle is true for all weapons so it doesn't matter:
At 60AL, vamp produces 1.9DPS more than sundering.
At 100AL, vamp produces 2.07DPS more than sundering.

So it's not a massive difference, but vamp undeniably produces more damage.

Plus if vampiric helps to get past prots and provides decent heals if you're using AoE attacks like Barrage or IA.

As you can see from the above table, even the calculated difference is very slight. There are no 'official' formulas upon which to base the calculations and in my experience they don't accurately represent the actual in-game results.

The bottom line is - use whichever one you want. You won't notice the difference in overall party damage output. But you will notice the difference if you forget to swap out your vamp weapon between mobs.

1. Well, yes, there are official formulas. The server code is a deterministic, algorithmic process. It is the official formula. Most of the formulas used by the community are either 100% accurate (meaning that we've figured out the precise algorithm used in the game code) or subject to rounding errors that result in a result that's never off by more than 1 (meaning we've figured out the overall algorithm, but not the exact order of the steps).

2. The reasons that in-game experiences don't match pencil-and-paper predictions boil down to (1) the person doing the pencil-and-paper prediction fails at math (idiocy); (2) the person doing the pencil-and-paper prediction did not take into account a particular variable that applies to the in-game experience (incomplete model); or (3) the person verifying their in-game experiences is trying to apply a prediction that expressly applies to situation X to situation Y instead (apples to oranges). Once you get people to stop making those mistakes, will will find that the formulas can predict results with no greater inaccuracy than a off-by-one rounding error.

Sundering would actually do more damage if it triggered on every hit (100%). The fact that it only triggers once every 5 hits (20%) is what kills it.

Vamp has the nice addition of self healing, as well.

By definition, "official" formulas would be the actual software calculations as supplied by the actual programmers.
No amount of "figuring out" would be "official" regardless of their degree of accuracy.

No, the person doing the in-game tests is simply observing the actual damage output numbers (usually against dummy targets) and tabulating them. There are no predictions and/or calculations involved in such a scenario. When done this way, there is little or no observed difference in DoT (Damage over Time) to Vampiric versus 20/20 Sundering.
And, further more, I submit that actual in-game data is necessarily more accurate and reflective of real in-game results, than any results that are derived by merely being calculated.

Look, if you were the programmer and your function was "damage = 2 * mastery" and I back-engineered it and came up with "damage = 2 * mastery," you could not seriously dispute that I now have the "official formula." If the formula is correct, then it's correct.

Are you saying that the predictions don't match the in-game results, or that you don't bother with predictions and just have a "feeling" that in-game results tend this way or that? If the former, it means you're calculating wrong. (When it comes to auto attacking dummies with sane values on the input variables, we know enough to get results that come within an off-by-one rounding error of 100% accurate.) If the latter, all that means is that your sample size is too small and/or you're letting cognitive bias skew your results.

For the sake of argument, I would like you to try things my way for a moment. I've written a nice little calculator so that you can avoid having to actually do any math. Once the bugs are found and ironed out, I will bet you dollars to doughnuts that it will give you predictions that match up with your in-game observations 100% of the time.

As for the "sundering vs vamp" question, I'm getting a feeling that you have a broader definition of "trivial" than most GW fanatics. I think that I might be able to eventually get you to agree to a proposition along the lines of "the difference between vamp and sundering is usually 5-10% of your total pre-buff damage output," and yet we would still disagree over whether that difference mattered.

Yes, but it's not "official". You shouldn't try to tell people you have "official" formulas, when you don't. "Accurate" or "correct" is, by definition, not the same as "official".

I've heard this before. People have suggested to me that my ~200 samples aren't enough, but I submit that if you need more samples than that to show the difference, then the difference is "trivial" given the much fewer number of hits in an actual battle.
Edit - that was ~200 samples in my original test. I did 2 more tests on only one AL of the dummy targets for a total of ~400 samples.

What my results are based upon is actually using identical weapons, except one is Vamp and the other is Sundering, against dummy targets and tabulating the total damage results. No calculations, no predictions, just actual real-time numbers. The total numbers between Vamp and Sundering were less than 5% different in all cases and in some cases the numbers for Sundering were actually higher than Vamp.

I don't give a flying fig about your calculated or predicted results, I'm only going by actual observed results.

(and yet again I find myself sucked into this stupid argument. I again challenge any readers out there to try it themselves and draw their own conclusions.)

What you observed on the dummy targets would be even less a representation of actual gameplay than the pure maths.

Take 2 rangers equipped and spec'd the exact same. Give the same bows except for strings. Auto attack using only the bows or same skills in same order. Very basic but you know who will win that. Vamp > 20% sundering not factoring healing. BUT FOR LAZY RANGERS WHO DONT WANT TO SWITCH WEAPONS, sundering is probably better cuz no degen while not hitting something.

Even if you don't switch, -1 degen isn't really dangerous.

Vamp is a little bit more annoying when playing with heroes, because they will waste time and energy healing you when you don't need it.

There is already a damage-calculating website that's been out there for a long time now that one can just plug numbers into. It should make things pretty easy to figure out.

The vamp degen is a little annoying, but if you don't switch between multiple bows already then you probably don't play a Ranger enough.

Now you're just playing semantics. My equally asinine semantic response is that there is an identity between to formulas that always give the same results for the same input. If f(x) = g(x) for all x, and g(x) is "the official" formula, then f(x) is "the official formula" by virtue of the transitive property.

They're not. (Also, it might interest you to know that the people who first derived things like the damage formula (Ensign, Son of Ra, etc.) used thousands of samples to generate their 95% confidence intervals.)

Linky linky?

This one, presumably. There are a few calculators on Guru (they're linked on the home page) that Ensign created ages ago too, but they're not as well integrated as this and yours.

Yup! That's the one I was referring to. Pretty accurate from when I compared it to the formulas given on the wiki. Though there was some minor differences that may have attributed to methods towards the rounding of numbers; they were small.