Short for super input/output, or super I/O, SIO is an integrated circuit on a computer motherboard that handles the slower and less prominent input/output devices shown below. When the super input/output was first introduced in the late 1980s, it was found on an expansion card. Later, this chip was embedded into the motherboard and communicated over the ISA bus. As ISA began to no longer be used with computers, SIO communicated over the PCI bus. Today, super I/O communicates through the Southbridge and is still used with computers to support older legacy devices.

Computer devices handled by the super I/O

  • Floppy disk controller
  • Game port
  • Infrared
  • Intrusion detection
  • Keyboard and mouse (non-USB)
  • Parallel port
  • RTC (Real-time clock)
  • Serial port UART
  • Temperature sensor and fan speed.

How do I know what IC is the super I/O on my motherboard?

Identifying the super I/O on your motherboard is easy if you look for an integrated circuit that is labeled with a company’s name that manufacturers super I/O chips. Some common super I/O manufacturers are Fintek, ITE, National Semiconductor, Nuvoton, SMSC, VIA, and Winbond.

Some newer chipsets are combining the Southbridge and super I/O chips into a single chip and referring to this chip as the Super Southbridge chip. Some manufacturers, such as NVIDIA and SiS, have even combined the Northbridge, Southbridge, and super I/O into a single chip.

Computer acronyms, Motherboard terms, Northbridge, Southbridge

  • Motherboard help and support.