40K: Psychic Phase – By the Numbers
A math guy takes a detailed look at the new 7th Psychic phase – Guess what he discovered?
According to MATH, the new psychic phase results in:
– Fewer powers being cast
– More selectivity over which powers you will push through
– Substantially more danger for the casters
– Denying is hard, if possible at all.
As we know, Math-hammer gives us a base of knowledge which, along with experience, informs our tactics. Since 7th hasn’t been out long, and the psychic phase seems to be the big hullabaloo, some numbers about the psychic phase would appear to be in order.
I checked both the probability of getting a cast off and the odds of getting Perils of the Warp for one through seven dice. I’m sure other people have done some of this work, too, but I aimed to be comprehensive. After that will be some discussion on the implications, and the real changes between 6th and 7th.
Casting Success Chart
All numbers rounded to the whole percent.
For reference, pass rates for psychic checks under the previous regime were:
Ld8: 72%
Ld9: 83%
Ld10: 92%
Perils: 6%
What does this tell us?
—Fewer overall psychic powers will be getting cast relative to the old regime. Let’s put this in familiar terms: say, an AM army with a brace of Primaris psykers. (Familiar to me, anyway.) At mastery level 2, casting 2 powers a turn, my expected return on psychic powers was 3.3 successes (Deny attempts notwithstanding). Under the new regime, with an assumed roll of 4 for warp charge, casting level 1 powers, I can throw two dice at each power and get off 3 with minimal Perils risk, or toss three dice at two powers and two at a third and get off 2.5 with a larger Perils risk. Throwing three dice lets me beat my Old Regime reliability, but at increased Perils risk; and however I do it, I’m getting noticeably fewer powers off. The limiting factor on casting is no longer the number of spells you know or your mastery level; it is now Warp Charge.
—You have more selectivity in which powers get cast. As part of my example above, I’m able to beat the old reliability numbers for my Ld9 psykers on two of my casts. Doing so, of course, drains me of other options. The real winners here are the Astropath and the Eldar Warlock, low-Ld psykers that previously struggled to get reliable casts. These days, by pumping additional Warp Charge into the Warlock from the other psykers in the Eldar army, you can easily up the chances of getting the low-cost Warlock powers off… if you don’t mind the increased risk of frying his brains.
—Perils is substantially more dangerous, particularly if you’re going for big-ticket powers. Any serious attempt to get a power off with either a) reliability or b) a Warp Charge cost of 2+ now invokes a serious prospect of pain. While there are ways to work around some of the lesser Perils effects, Mental Purge and Warp Drain are both consequential problems for psyker-spam armies.
For illustrative purposes, let’s conceive of a daemon-spam list that can generate 28 Warp Charge a turn. To get the summoning powers off, all of which are Warp Charge 3, and devoting seven dice to each power, you’d expect him to get off 3 of his 4 casts and get 4/3s Perils. I think that can be dealt with.
Finally…
It’s hard to Deny Blessings, but it can be done… …just don’t bother with half-measures. The odds of Perils, incidentally, are the same odds of Denying an enemy blessing that got two successes. As you can see, the numbers don’t really start to get respectable until you get up to 7 dice, and even then it’s only 1-in-3. Unless you’re playing psyker-spam yourself, the way to go would appear to be to select the power you really, really want to Deny (say, Invisibility…), and throw all your dice at it. It also appears that Conjurations, which by necessity require three Warp Charge to go off, are going to be quite difficult to counter.
~Not exactly the initial kneejerk reaction everyone had to the phase is it…
