The SiS645 Chipset -
A Breeze Of Fresh Air For Pentium 4

SiS new and first Pentium 4 chipset looks already quite sexy just on paper.

The SiS645 North Bridge comes with the following features:

• Full Pentium 4 Support (Willamette/Northwood - Socket423 / Socket478)
• DDR SDRAM Support For DDR200, DDR266 and DDR333, up to 3 GB with 3 DDR266 DIMMs or 2 GB with 2 DDR333 DIMMs
• SDRAM Support For PC100, PC133
• AGP 4X Support, Fast Writes Support

The SiS961 South Bridge has the following feature list:

• ATA100 support
• Dual Independent Open HCI USB Controllers for up to 6 USB ports
• Integrated MAC controller
• AC97 compliant integrated 5.1 audio controller
• PCI 2.2 compliant, up to 6 PCI masters

Besides those features, SiS connects the 645 north bridge and the 961 south bridge with a new 16-bit wide interface, clocked at 266 MHz, which is called 'MuTIOL'.

Similar to the StreamThrough-technology of NVIDIA's upcoming nForce chipset using HyperTransport protocol between north and south bridge, the MuTIOL from SiS is also designed for multiple isochronous virtual channels. The 16-bit wide bus clocked at 266 MHz provides a bandwidth of 533 MB/s up- as well as downstream, which beats all other chipset interconnects so far. It is questionable if this high bandwidth is really needed today, but it's always good to know you've got some headroom.