The simulations don't account for anything beyond mechanical latency, which is averaged below even expected mechanical throughputs (Re: G15 Keyboard). 0.15 seconds is roughly the minimum latency one can expect in a "perfect" setting. The simulation assumes 0.05 to 0.15 average. Meaning, beyond underestimated mechanical latency, the simulation doesn't even support human or UI (FPS -- worse in some raid settings) latency.

Also, the simulation uses 6.0 second SW: D.

All that being said, real world practices will dictate nearly twice as much as the simulations quote (9+ crit : 1 dmg), and that is still tipping the scale towards perfect conditions where you can and do always use talented MB and SW: D on cooldown.

Ultimately, there is no itemization -- that I have seen -- that supports anything beyond looking at maximum +dmg in the slot. There are a select few items supporting huge +hit increases, with the loss of ~1-2 +dmg, to enable reallocation of Shadow Focus talents.

Can you recommend a more reasonable value? Every time I push up the lag input too high the stopcasting-maestros chew me out.

It uses a 6sec SWD if you specify a 2.1.0 patch level. By default it will use 12sec cooldown.

I don't know if it would be advisable to up latency much in your simulations, I don't think it's that unrealistic with stopcasting macros. Yes you have reaction time and various latency from your keyboard button to the server but thats why you're hitting the button early. I personally at least would also prefer if it leaned more towards optimal best case scenario than conservatively high.

For VT threat I guess the people working on omen and threatlib knows how it works exactly? I think last I heard was as someone posted above that VE healing is all counted towards the priest while VT manaregen threat is attributed to each person. So in that case 5% of your damage causing a half point of threat extra? i.e. fairly negligible. Would be nice with confirmation once and for all though.

VT counting as threat for the person gaining mana is a relic from when they changed Blessing of Wisdom. It's not like that, VT threat is attributed to the person giving it -- in this case, it's attributed to the shadow priest, because he's providing mana. However, the amount of threat is pretty negligible because, well, it's 5% of your DPS as mana, and all 'gains' of this count count as half threat. So, even in a mana starved group (almost every single one you're in), it counts as another 1.8% threat allowing for Salvation, or 3% if you have nothing else. Not really much to worry about at all.

1) Are you using Salvation? Even if you only have a single paladin in the raid this should be your pally buff.

2) Imp fade is worthless as it is not a permanent threat reduction. It is also a waste of a GCD. Drop this talent for something more useful and stop using it every CD. It's only really good on fights with a lot of adds or one with many aggro resets/drops (Tidewalker, Leo the Blind, etc.). Again, fade is a temporary drop of something like ~1k threat.

3) You can dps to 130% of your tanks threat until you pull aggro. On Gruul you do not have to be below the 2nd tank unless you are standing in melee range, which you should never be doing.

4) If threat is still an issue (it shouldn't be if your tank is generating proper threat), drop VE and make sure your healers pick up the slack.

Emanonevahi-

First off, get rid of improved fade. It's only a temporary aggro dump, and it's not worth 2 talent points.

As for Gruul, since you're ranged, you can go above the OT. Only the melee have to worry about staying below him. Since you're still 10k below the MT, keep pushing the damage. If you're still having threat issues, then start to back off on your big spells starting with SW:Death first, then mind blast. A simple VT/SW:P/Flay rotation should provide a good amount of dps, and hopefully you shouldn't even be able to pass your tanks when using something like that. If that still doesn't help, politely ask your tanks to generate more threat (good luck with that!).

As a side note, your spec and gem selection needs work. For the gem selection, just use +dmg gems in your FSW set...you're way above 76 hit rating as is. Once you hit 76 hit rating, then all you need to focus on is more damage. As for your spec, I'd like to imagine that you're going to run into a lot of mana issues unless you have druids that love you (even with chain-chugging mana pots). Make certain to drop improved fade, get rid of shadow resilience (unless you really love to do pvp), and move more points into discipline. A cookie-cutter 14/0/47 build works fine for quite a few of us. I personally use this build for PvE raids. There are plenty of other builds out there that work as well, but it just will all depend on personal preference, whether there's another shadow priest in the raid with you (which is why I'm only 4/5 shadow weaving), etc.

Using a G15 keyboard, I haven't been able to use a latency / stopcast macro less than 0.16 seconds (average) apart. I believe Manly <Elitist Jerks> has had the same experience. Effectively, I've not been able to /stopcast with less than spellcast_time + 0.16 and have 100% uninterrupted casts. This is using a mechanical device, which is bound to average better than human error, even assuming the device is adding some latency to the process.

If I read right, the latency, in the simulation, averages between 0.05 and 0.15. The maximum alone is below my minimum experience. Mileage may vary of course, if others have shown better /stopcast deltas. I'd love to see and hear more about the circumstances.

Sorry about this. I browsed -- apparently too hastily -- through the latest CVS and only found the SW: D at 12sec. Are the matrices on SimulationCraft/Scaling/Priest using a 12sec SW: D sim? The results struck me as best-case for my pre-2.1 sims, and didn't think to look further for consideration to the 2.1 changes elsewhere in the source.

In addition to the other suggestions, take Shadow Word: Death out of your rotation. You shouldn't use in every cooldown without Embrace up, and it essentially has a +50% threat component if you include the healing from the extra damage incurred.

If you are getting salvation and still pulling aggro, then I'd suspect your tanks aren't maximizing their threat generation. Perhaps post a WWS so we could take a look at it?

Thanks for the Great help everyone, I really appreciate the tips.

Yes, my gems do suck, they were gems i put on before my hit rating got so high. Im only at 7.61% though. Plus talents = 17.61% and should be at 17% right? So I am not that far over. I can lose a few points though. Just waiting to afford +9dmg gems.

I will look into my spec a little more I guess.

Here is the WWS from our last Gruuls Lair run. (no, we havnt killed him yet.)
Wow Web Stats

I guess I can go over the tank even for aggro on gruul, but on other bosses this really wouldnt help. I have to get back to work, will post more later.

Looking at your tank in the fourth Gruul attempt, he really needs to work on threat generation: Caillou - WWS

In almost 4 minutes, he has 12 Shield Slams, 10 Revenge, and 15 Shield Blocks refreshes. His talents seem a bit odd too. He doesn't use Heroic strike once but has 3/3 Imp Heroic Strike, at the cost of 0/3 Improved Defensive Stance.

Contrast this with Paches from an EJ kill which also took slightly under 4 minutes: Paches - WWS

In the same time, Paches did 21 Shield Slams, 17 Revenge, and 27 Shield Blocks. Oh, and he also did 65 Heroic Strikes.

PS: Your tanks also need amplify magic.

Thanks again for all the help guys. I have looked over the WWS from both players more in depth. I was able to pull some pretty useful information about this. It really helped having another tank to be able to compare to.

Paches amazing 154 abilites used during the timeframe Vs Caillous 54 abilities.

Ive posted a bunch of this up for my guild, boy can I see one mad tank when he reads all this. No tank likes to hear hes doing a bad job eh...

Is anyone interested in looking at my WWS from Maybe that same fight, Gruul #4 and Maulgar (kill) and see if they see a problem with what I am doing? I am already going to go look at my spec and fix the issues there. Thanks a ton for the information about Fade. I had no clue it was only a temporary threat reduction... I thought I was losing the 1-2k threat every time I used it :P

Next I will look for some tanking rotations for him to review...