While the Northbridge is directly connected to the CPU, the Southbridge microprocessor is not. The Southbridge takes care of the data flow to the slower peripheral functions. Below is an overview of key buses and standards managed by today's Southbridge chips.
- SATA (Serial Advanced Technology Attachment) control for mass storage to interface disk drives.
- PATA (Parallel ATA) control for mass storage to interface disk drives, also known as IDE (Integrated Drive Electronics). Officially known as ATA (Advanced Technology Attachment), but now usually dubbed PATA to note the difference with SATA.
- BIOS (Basic Input Output System) memory.
- Low Pin Count interface (LPC) controller for serial, parallel, game port, PS/2 mouse/keyboard, infrared interface, floppy disk controller, several general purpose I/O pins, fan speed control.
- SMBus, an interface to external 'health' checking sensors of the system, for e.g. fan speed and temperature.
- Interrupts, DMA controllers.
- Real-time clock (RTC).
- USB (Universal Serial Bus) controller.
- IEEE 1394 (Firewire) controller.
- AC Link (Audio Codec Link) interface provides on-board audio and telephony (modem/networking) facilities.
- Integrated network (LAN) controller. System designers are looking to move network processing from expansion cards to the Southbridge. For servers there is an opposite trend, where networking is preferably delegated to dedicated cards in order to offload the CPU.
- Power management to allow the computer to sleep or shut down to save power.
Courtesy of the French Energy Agency ADEME, Future Electronics project. Expanded by VHK.