[Long Haired Git]

Energy never "appears" or disappears.
It gets changed into different forms, but never dispappears.

Pump X draws 10W from the power socket. This electricity goes from a high potential state to a zero potential state in its voltage. That potential energy is transformed into other things. Assuming the pump and the rest of the rig are held perfectly still, there is zero net movement energy. Assuming perfect silence, there is zero noise energy. Thus, where does the energy go? The answer is heat. The pump motor is not 100% effecient and it gets hot. Ditto for the pump part. Even the movement of the water results in heat (again assuming tubing is still and everything silent). The friction of the coolant on the walls of the tubing and components converts kinetic enery of the coolant into heat. The pump and tubing and components then leak this heat into the air. Some of the heat from the pump's motor and the pump itself is lost to air from the pump body and doesn't impact water temps.

If a video card is indeed consuming 138W of energy you need to figure out where this energy is going. Assuming the cable to the monitor doesn't transfer many amps of electricity, assuming not much electrical power is returned to the motherboard using return lines, and assuming the video card doesn't power a fan and is perfectly silent, then indeed all 138W will be released as heat.

How much comes out the GPU is a question. Heat can be lost over the entire surface of the card plus also via sinks into the motherboard and also the back-plate is another question.

Wow, 138W? Really? Most modern CPUs only consume 90W or so.....

I suppose heavy over-volting and over-clocking can help...