Northbridge is also called memory controller hub (MCH) (or GMCH in the case of integrated graphics). It contains the processor interface, DRAM controller, and x16 PCI Express graphics port. It communicates with southbridge over the DMI (direct media interface). Southbridge is also called I/O controller hub (ICH) that contains the PCI Express interface, the PCI interface, LPC interface, USB2, SATA and other I/O functions. Wikipedia includes nice articles on
northbridge and
southbridge.
Major differences are:
- ICH7: 1 x PATA, 4 x 3.0Gbps SATA; Integrated 10/100 Mbps LAN controller; 8 x USB 2.0
- ICH8: No PATA, up to six 3.0Gbps SATA, external SATA; Integrated Gigabit LAN Controller; 10 x USB 2.0
New functions added to ICH8 are:
- Intel Quiet System Technology
- Simple Serial Transport (SST) Bus and Platform Environmental Control Interface (PECI)
- Intel Active Management Technology with System Defense (ICH8DO only)
- SMBus, faster speed, up to 100 kbps
- Five Integrated Voltage Regulators for different power rails
- Serial Peripheral Interface (SPI) supports up to two SPI devices and 20 MHz and 33 MHz SPI devices
Please read the ICH8 datasheet at the Intel site to see what these mean.