Northbridge - Chip 1 of 2
Why is it called a chipset? Because in the past there were always two or more of these on a motherboard.
Some motherboards now have only one chip that performs all of the duties of the chipset, but others still
use two or more chips. Chipsets are like the motherboard's traffic cops. They direct the flow of data from
one point to another. Each chip in the chipset has its own particular job. This is chip 1 of 2 chips
in the 440BX chipset. It is called the "Northbridge." It is the more important of the two, because it
links directly to the microprocessor. Above is a picture of the 440BX chipset. Below is Chip 1, the
"Intel 82443BX PCI/AGP Controller." It is hidden under a heat sink that protects it from overheating.
The 82443BX Northbridge chip controls the data traffic between the microprocessor and the rest of the
motherboard. It also controls the traffic to and from the AGP card. Both chips share in the task of
controlling the PCI and main memory data flow. In the diagram below you can see the data flow paths
mapped out for the chipset. Notice that the paths managed by chip 1 are shown in red. The duties of
the Northbridge chip may vary slightly depending on the chipset. For some chipsets, the Northbridge
may control the CPU, video, and main memory traffic, while the "Southbridge" chip may control the
The paths between each component are referred to as "buses." Buses are simply the paths, or wires,
that connect one component to another. The chips in the chipset are referred to as bridges, because
they bridge the components together and ensure that the data flow is directed to the proper place.
The better chipsets are those that can handle data the fastest and most efficiently. Below is a
picture of both of the chipsets on the motherboard.