The southbridge is one of the two chips in the core logic chipset on older personal computer (PC) motherboards, the other being the northbridge. As of 2023, most personal computer devices no longer use a set of two chips, and instead have a single chip acting as the 'chipset', for example Intel's Z790 chipset.
IBM T42 laptop motherboard with the following labels: CPU (central processing unit), NB (northbridge), GPU (graphics processing unit), and SB (southbridge)
In a computer system, a chipset is a set of electronic components on one or more integrated circuits that manages the data flow between the processor, memory and peripherals. The chipset is usually found on the motherboard of computers. Chipsets are usually designed to work with a specific family of microprocessors. Because it controls communications between the processor and external devices, the chipset plays a crucial role in determining performance.
Intel i945GC Northbridge with Intel Pentium Dual-Core E2220 2.40 GHz on an Intel D945GCCR motherboard (c. 2007)
Part of an IBM ThinkPad T42 laptop motherboard showing the CPU, GPU, Northbridge (NB), and Southbridge (SB)
Intel Cannon Lake Platform Controller Hub (PCH) die