Quote Originally Posted by Calmatory View Post
And to add to this, TDP is related to the cooling solution only. TDP is the value the cooling solution has to be able to dissipate without the chip reaching it's maximum junction temperature. In other words, if a GPU has TDP of 130 W, the actual card can consume even 300 W in some cases.
1.) as the TDP is related to the cooling solution, other components such as VRM, VRAM, board may consume whatever they please and as long as the cooling solution isn't designed to cool them, it does not affect TDP.
2.) Under some workloads(e.g. Furmark), the chip may dissipate much more heat than the cooling solution is designed to handle, as in most cases TDP does not represent the maximum theoretical power draw of a given chip, but rather the typical power consumption under real world workloads for which the chip has been designed for.

Hence why TDP itself isn't good estimate of whole card's power consumption, and why MBP isn't good estimate of only GPU power consumption.
Exactly. In addition, neither takes into account the efficiency (or lack thereof) of the VRMs, etc which can have a siginificant impact upon overall power consumption of a given design.