Wikipedia
A northbridge or host bridge is one of the two chips in the core logic chipset architecture on a PC motherboard, the other being the southbridge Unlike the southbridge, northbridge is connected directly to the CPU via the front-side bus (FSB) and is thus responsible for tasks that require the highest performance The northbridge, also known as Memory Controller Hub, is usually paired with a southbridge In systems where they are included, these two chips manage communications between the CPU and other parts of the motherboard, and constitute the core logic chipset of the PC motherboardOn older Intel based PCs, the northbridge was also named external memory controller hub (MCH) or graphics and memory controller hub (GMCH) if equipped with integrated graphics
Northbridge_(computing) - Wikipedia, the free encyclopedia