I am trying to understand why GPUs consume so much power. For example, the max power consumption of the P100 GPU is 250W.
As I understand power is measures in watts as current x voltage. Given a fixed power source (i.e. voltage), I would assume that GPUs draw a lot of current. If I understand this correctly, why does a GPU draw so much current?
I think GPUs mostly consist of transistors? So why does the configuration of transistors in a GPU lead to more power being consumed than in a CPU?
Thanks!
Best Answer
A GPU is basically a LOT of simplified CPUs in parallel. Each of them is not as capable and flexible as a real CPU, but there are thousands of them to give this massive parallel computing performance.
But this also means that it takes many billions of transistors to build a modern GPU. And for logic chips we use FETs, so with every clock cycle all the billions of gate capacitances have to be charged and discharged. This is where the large amount of power is going.