For the people who are doing this successfully, what's the total DPS you need to do to bring him down? I've seen people say that having 3 healers + 2 tanks (totaling 4k dps) and then another group putting out 25k dps total (5k/each) is the key.

Am I crazy? Are these people overstating it? What kind of gear is needed to reliably put out 5k dps, anyway?