Disintegrate Cost Reduction gear, Diamond Skin (Prism), Storm Armor (Power of the Storm), using the slightly higher proc coefficient runes (Entropy and Intensify), Familiar (Arcanot), and Magic Weapon (Conduit) in roughly that order will reduce the channeling costs of disintegrate and make this build stable with less APoC.
Disintegrate Cost Reduction Affix appears on Rare Helms (up to -5 cost), Stone of Jordan (up to -5 cost), Skull Grasp (up to -4 Cost), and Mara's Kaleidoscope (up to -5 cost), meaning you can actually completely zero the cost of disintegrate from just gear.
Disintegrate is pulse rate 3, meaning it pulses three packets of damage per time it charges the arcane power cost, and has a proc coefficient of 0.167 (no runes, entropy, or intensify), 0.111 (convergence or chaos nexus), or 0.125 (volatility).
Disintegrate Cost * attack speed - coefficient * crit chance * 3 * APoC = AP deficit, which becomes infinitely sustainable when the AP deficit is less than your AP regeneration (10 + 2 for astral presence + 2 Arcanot + 0.5 Templar + 2 4pc Tal'rasha). I'm going Eyebal and guess that the build is fine for low monster power as long as its AP deficit after accounting for regen is less than 10 (for 12ish seconds of channeling uninterrupted) then the build is sustainable.
The OP's profile shows the following:
41.5% Crit Chance
1.68 attacks per second
0 Disintegrate Cost Reduction
Chaos Nexus, Astral Presence, Templar
Coefficiet is 0.111, AP Regen is 12.5 per second
18 * 1.68 - 0.111 * 0.415 * 3 * 27 = AP deficit = 26.5, which actually gives an adjusted deficit of 14 AP per second, meaning 8-9 seconds continuous channeling before AP runs out.
So lets generalize this formula for a second to see if we can determine some the value of some of our various ways to offset the channel cost:
The coefficient for Chaos Nexus is 1/9, and intensify which would be my choice is 1/6. If we assume a 1.0 attack speed and 50% crit chance for a second we see that our formula becomes:
(18 - cost reduction) * 1 - (1/9)*(0.5)*3*APoC = AP deficit for chaos nexus. This tells us that APoC in this case has 1/6th the value of cost reduction. Adding attack speed increases this ratio in favor of cost reduction. 6 APoC is also worth 1 AP regen in the overall result here. Intuitively we see that attack speed will not change the relative value of APoC or AP regen, but will increase the value of cost reduction.
If we switch to Intensify, the value of APoC increases by 50%, meaning switching to intensify allows you to drop 1/3rd of your APoC without a noticable difference, i.e. going from three sources to two. Each 1 point of disintegrate cost reduction equates to 6 * attack speed points of APoC for Chaos Nexus and 4 * attack speed points of APoC for Intensify.
This means if the OP were to change Storm Armor (Shocking Aspect) to Storm Armor (Power of the Storm) he would be able to drop 2 of his 3 APoC sources without reducing his AP efficiency. If he were to swap one of his rings for a -5 Disintegrate Cost Stone of Jordan as well, he could drop APoC entirely without affecting the builds performance, and swaping his DS rune to Prism would have a similar effect.
Edited by DisposableHeero, 19 November 2012 - 03:01 PM.