Most know SIS as being
the producer of value segment computer chipsets, and while that was true,
a while ago; SIS today is moving into a more serious market with its latest
solutions for the Pentium 4 and AMD Athlon processors.
The SIS 645 for the Pentium
4 is quite a unique solution with its support for DDR333 memory, which is
capable of driving a bandwidth of up to 2666MB/s; higher than any DDR support
available on todays Intel and VIA chipsets.
The North Bridge offers
support for SDRAM as well as DDR266 and DDR200; most boards featuring the
SIS 645 will likely use DDR due its higher bandwidth over SDRAM.
The transfer protocol
between the North and South Bridge is designed for multiple isochronous virtual
channels, its 16-bit bus wide bus running at 266MHz provides a fully bi-directional
channel that transfers data at up to 533MB/s. Features provided by the South
Bridge include the practically the same you would expect from an Intel ICH2
or VIA South Bridge, including AC97 v2.2 audio, Ethernet, dual channel
USB, up to six USB 1.1 Ports and IDE Ultra ATA 100 support.