From the guru3d review, 600w for the beast with 15amps for each connector (check your psu's amperage per rail).
Seems like the D13 has the thermal limit @ 90°C (hardwarecanucks). Guru and the canucks had temps ~80-85c with the fans in low, but turbo (highest) cooled it to the mid 70s but you gotta contend w/ the extra noise.
Oc'ing, they got to 1100 but had trouble with temps higher then this (guru3d).
Overall, it has the potential to push higher then the 295x2, but its very held back, primarily by the cooling at this point. If you don't plan to go this extreme, its still a good choice imho. just gotta keep that card extra cool Edited by wermad - 6/24/15 at 9:52pm