Intel has its ICH family, NVIDIA uses the MCP naming
convention, and VIA sticks to the traditional south bridge
nomenclature. ATI's 'southbridge' equivalent is called an IXP, the I/O communications processor responsible for interfacing
Its top-end offering, the
IXP 250, is capable enough, but it lacks some of the nifty features found on
instance, whereas the IXP 250 supports six USB 2.0 ports, Intel's ICH5 boasts
eight. Furthermore, Intel offers gigabit Ethernet through the CSA
architecture. ATI, on the other hand, has an integrated
3Com controller that tops out at 10/100 speeds.
While ATI facilitates six-channel audio through an AC'97 codec, it is
in no way as advanced as NVIDIA's MCP-T (Soundstorm) and its Dolby Digital
encoding capability. Finally, the IXP's most glaring weakness is a lack of Serial ATA
support, something both Intel and VIA have already added to their respective
arsenals. It does support Ultra ATA-100 drives however.
looking to supercede the IXP 250's capabilities have the option to connect a
third party south bridge via the PCI bus. Unfortunately, communication is
limited to 133MB per second this way, compared to ATI's proprietary 266MB per
second A-link bus.
Phil Eisler, vice president and general
manager of ATI's integrated and mobile business unit, the IXP is scheduled
to be revised later this year. I would expect to see native Serial ATA support
and additional USB 2.0 connectivity brought on board by that