Allow me to make it clear how this works. Here is the timeline starting with the first, priming iteration.

00.0: IT
01.5: PS
03.0: HS
04.5: HS
06.0: DS
07.5: DC
09.0: GCD Ends, but the first Frost Rune hasn't refreshed yet.
10.0: F refreshes, but the first Unholy Rune hasn't refreshed yet.
11.5: U refreshes, DS
13.0: HS
14.5: HS
16.0: HS
17.5: HS
19.0: DC
20.5: DC, end of the first iteration
21.0: Because of the notable delay in the first iteration, you would get additional DoT ticks here from 2/2 Epidemic.
21.5: UF Refresh
22.0: GCD ends, IT.
23.5: PS, this rune will refresh at the same time as the F rune.
25.0: HS
26.5: HS
28.0: DS
29.5: DC
31.0: GCD ends, but we still have a second before the UF refresh.
32.0: UF refresh, DS
33.5: HS
35.0: HS
36.5: HS
38.0: HS, it has been 16 seconds since we used IT.
39.5: DC
41.0: DC, end of the second iteration
42.0: UF runes refresh
42.5: GCD ends, IT, continue ad nauseam.

Compare what you have been doing against that timeline. You should be able to see A) why it works and B) what it is you're doing differently.

Based on this, couldn't you just RP dump again at 9.0 seconds instead of 20.5 seconds? These would leave you with only requiring pushing to the ideal rotation from 21.5 seconds to 22.0 seconds periodically, instead of every time. Of course this would require RPM to not DC below 25 during that dump phase without energy loss, since you are opening with DS. Worst case you enter 11.5 seconds with just under 65 RP, and reach ~130 when you hit DC range at 19.0 seconds.
Overall though, I would argue for the second point of epidemic. Take Salviastria's wws on page 4. One extra tick for 550 damage per disease every ~22 seconds is a 50 dps increase. He did 5.450k dps, the extra ticks are worth 0.92% dps* on their own, in addition to the effects of not losing disease buffs to HS due to fight mechanics breaking up the rotation. If you remember from earlier in this thread, morbidity is worth ~0.5-0.6% dps per talent point, making epidemic a higher priority talent to max then morbidity, ignoring the DnD CD reduction.
Based on this I advise we assume 2/2 epidemic is worthwhile and move to:
morbidity vs rav dead... morbidity we basically know, but rav dead calculations need to be specified: NotD or no NotD.

*Edit: Due to rune grace period the extra ticks from 2/2 epidemic are limited to the opening rotation, and places where dps contact is lost. So the disease ticks would yield lower than a 0.92% dps increase.

Is there an reason why you dont start with DS for an Abomination's Might buff right from the start?

This would although change the timeline, like


00.0: IT -> DS
01.5: PS -> IT
03.0: HS -> PS
04.5: HS -> HS
06.0: DS -> HS
07.5: DC -> DC
09.0: GCD Ends, but the first Frost/Unholy Rune hasn't refreshed yet.
10.0: F refreshes, -> F/U aka D/D refreshes, HS
11.5: U refreshes, DS -> HS
13.0: HS -> DC
14.5: HS -> HS
16.0: HS -> HS
17.5: HS -> DS
19.0: DC -> DC
.
.
.

Going backwards, you only get the extra tick on "priming" iterations or when movement forces you away from a boss. That may be often enough to make it worthwhile, or it may not. The lost HS argument doesn't resonate with me, as most events I've experienced which separate you from a boss do so to an extent that makes the point moot.

To answer your first question, if you have the RP for it you have a good point, a half second can be shaved off the priming iteration by using DC twice there and only once after the second half. If you don't have the RP you probably want to skip the DC at 20.5 seconds anyway in order to build RP.

You may actually end up skipping the third DC fairly often. With DRW being used every 90 seconds, you need to store 100-130 RP over 4.5-5 rotations, effectively requiring an average surplus of 25 RP per rotation. However, if we use 3 DCs every rotation we have a deficit of 2 RP (110 RP generated from runes, 8 from Butchery). Thus you can only use a third DC once or twice out of 4-5 rotations, barring outside effects generating RP (such as Resto Druids and Disc Priests).

Mostly because I was caught up in making it clear how, through repetition and what I thought was a simple example, the gap between the final HS and diseases dropping widens. In a "real world" scenario you should definitely open as you described.

Correct me if I'm wrong, but are you objecting to my claim that the Unholy rune used at 23.5 seconds will refresh at the same time as the Frost rune used at 22.0? If so, the following section of the TTT might be useful reference.

Death Knight: PvE DPS

If not, I'll have to ask you to be more specific, as otherwise I don't know what it is that's wrong.

Hey new guy here.

I was curious as to why more mention hasn't been given to Glyph of Disease. I have been trying to do a rotation seems to be working out decently, other than I don't have my mind wrapped around pushing the pushing the Pest hotkey instead of my IT/PS keys.

DS (UF), IT (F), PS (U), HS (B), HS (B)
HS (D), HS (D), DS (UF), HS (B), Pest (B)
DS (UF), HS (D), HS (D), HS (B), HS(B)
HS (D), HS (D), DS (UF), HS (B), Pest(B)

Obviously, RP dump in there.

I havn't counted but I think you would gain an extra HS in this mess. Thoughts anyone?

Btw, im running with 51/2/18 with 2/2 Epidemic.

A lot of mention has been given on this very subject (more than necessary, in fact), at least once per page and in the old blood thread as well. This is not new and amazing information. The skinny of it is, it is not worth the loss of a major glyph spot. Do a search for more detailed information, but it has been theorized and tested to not be as efficient as just re-applying your diseases.

That's what I was missing. Thanks.

You may want to read, like, any page in this thread. It gets brought up a lot. I think the concensus is that it's the best third glyph you can get until you find someone who can make DRW.

Yes, the ghoul in a 44/0/27 build will scale with raid buffs. It works just like a hunter pet as in it will double dip on buffs (gets stats from you + your buffs and buffs tossed on it). I have been seeing some very nice numbers out of this build myself. However, in the build i am running, I have 2 points in Impurity instead of Dirge, and took GoDisease over Dark Death. I am not sure if Dark Death will give more DPS on this build since with Disease I can refresh my diseases with one rune vs. two therefore I am able to get in another HS on the refresh rotation.

44/0/27 Any pointers on this build are extremely welcome.

Using actual parsed average values from a WWS report on Sarth:
IT damage + PS damage + HS damage = 1165+ 1344 + 2548 = 5057
DS damage + Pest damage = 3776 + 0 = 3776

I realize that one has 3 GDCs and the other has 2 GDCs but it is easy to see why the 3 runes are more effective at producing damage using IT, PS, & HS then DS & Pest.