Update (3 May 2011): Patch 4.1 has changed Frost Death Knights again, so now the use of Unholy presence is viable and desirable, but the jury is still out on exactly which circumstances require which presence. For now use Unholy for Frost, especially if you have a need for high movement.
Old info (9 March 2011): Cataclysm has totally changed the choice of which presence to use. Please do not use Blood Presence for DPS any more, its a Tank Presence now. I have written an updated post on this topic, but the content is repeated here.
From now onward the choice of DPS presence is between Frost and Unholy. Generally if you are an Unholy DK, then use Unholy Presence especially where fights require a lot of movement. Also if you’re a Frost DK then use Frost presence for dual-weild and Unholy for using a two handed weapon (see links for proof). This is a deliberate change in style so that the spec matches the presence.
So the DPS rule is now: 2h weapon = Unholy, x2 single handed weapons = Frost.
Original post is below.
I ping’ed a question about Unholy vs Blood presence for Death Knights in PvE, to Skeleton Jack. The response left little doubt in my mind of his opinion.
Noted SJ, I won’t ask again. 🙂
How about this old topic: Unholy vs blood presence, as a blood spec dk
I was doing HoA (? big boss that is a 4 minute dps race), and was told to switch from Blood to Unholy. Could the reason be the fight being very short? The reason I ask is that I thought that blood was better overall, and increased the damage on all abilities.
I’ll have to try some target dummies. And then I remembered you posting something along the lines of “blood always for dps pve” and it got me thinking.
The response goes:
DO NOT USE UNHOLY PRESENCE TO DO PvE DPS OR I SWEAR TO GOD I WILL BEAT YOU WITH A STICK!!!