With bosses being the endpoint of an act and the one thing stopping you from progressing to the next one (aside from gear, RMAH, and drop rate woes) Blizzard implemented enrage times on both bosses and champion/elite packs. However what those enrage times mean and when you hit them are not exactly common knowledge. Thankfully Furies on the Diablo 3 forums compiled a handy guide in order to know exactly what you are up against.
Bosses with (?) next to them don’t have enrage timers, but not confirmed.Elite champ packs have an 8-minute enrage timer in HELL (I personally tested this) Elite champ packs have a 4-minute enrage timer in INFERNO (I personally tested this) The following suggested DPS is for a Barbarian with with Frenzy (Sidearms), WotB (Insanity), and playing solo. DPS will need to be increased for other classes and will vary due to skill chosen.
Magda: None (?)
Zoltun Kulle: After 3 minutes, he will teleport to you and one-shot you (reported as bug due to different from described in patch notes). – 13k DPS
Belial: 3 minutes into Phase 3, he will cast meteors that will cover the whole floor. – 15k DPS
Ghom: After 4 minutes, gas clouds will spawn 2 at a time, last longer, and spawn quicker. – 17k DPS, needs very good gas cloud placements BEWARE
•Watch from barb perspective: http://www.youtube.com/watch?v=8bySHCfTZHo
•Watch from wiz perspective: http://www.youtube.com/watch?v=twGIOCme2Pw
Siegebreaker: After 4 minutes, he puts a DoT on you that increases in damage – 17k DPS
I’m not a huge fan of enrage timers on the bosses, but having knowledge of what I am up against will not have me throwing myself against something I can’t handle. Having read this I can rest assured that my Monk would be facing some challenges in the later acts, especially on ZK and Ghom. Often I would go into a boss fight not really knowing what might happen, You can’t really do that in Hardcore Inferno since that one time is all you get. For those of you( softcore or Hardcore) hitting the brick wall perhaps this info will help you get past it. If you have any other info on any boss feel free to let us know in the comments below and I’ll add it to the post!