It is mostly used on gaming laptops which usually have an integrated graphic device and a discrete video card.
The Northbridge is one of the core logic chipset that handles communications between the CPU, GPU, RAM and the Southbridge.
The way how it works usually has the following process (refer to the Figure 1. on the right):[1][2] The Southbridge is a set of integrated circuits such Intel's I/O Controller Hub (ICH).
It handles all of a computer's I/O functions, such as receiving the keyboard input and outputting the data onto the screen.
The way how it usually works usually has two steps:[3] The reason why the second step can be optional is that sometimes the rendered the data is outputted directly from the discrete graphics card which is located on the graphics card slot so there is no need to output the data through the Southbridge.
Disabling them when no heavy graphics processing is needed can significantly lower the power consumption.
This technology also introduces a new power control plan that allows the discrete graphics cards consume no energy when idling.
They are commonly known as:[9][10] The most popular dedicated graphics cards are manufactured by AMD and Nvidia.