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The SiS755 chipset

Athlon 64 core logic from the other guys

NVIDIA AND VIA HAVE dominated the enthusiast market for Athlon 64 chipsets, but they're not the only ones with core logic for AMD's latest processors. SiS has quietly been churning out the SiS755 chipset, which is seeing a lot of action in Socket 754 boards from ECS, ASRock, and Foxconn. Now these manufacturers aren't exactly known for enthusiast-oriented products, but with price tags hovering around $85, their SiS755-based Athlon 64 boards will certainly be appealing to those on a tight budget.

Six months ago, I wouldn't have even uttered "Athlon 64" and "budget" in the same breath. Today, however, relatively inexpensive chips like the Athlon 64 2800+ are making the Socket 754 platform a more affordable option for cash-strapped enthusiasts and anyone else who desires 64-bit compatibility and better media encoding performance than the Athlon XP can provide.

Looking at price alone, the SiS755 is certainly an attractive option, but can the chipset's features and performance keep up with its Athlon 64 competition? We tested a SiS755 board against VIA's K8T800 and NVIDIA's nForce3 150 and 250Gb chipsets to find out.

The SiS755 north bridge...and SiS964 south bridge

The chipset
The SiS755 chipset is made up of SiS755 north bridge and SiS964 south bridge chips, which come with all the usual integrated features. On the north bridge, the SiS755 houses an AGP 8X interface and 16-bit, 800MHz bi-directional HyperTransport link, but that's about it. North bridge chips for AMD64 processors haven't been all that interesting since AMD took the memory controller, which is traditionally a north bridge component, and moved it onto the processor.

A block diagram of the 755 chipset. Source: SiS.

SiS links its north and south bridge chips with a proprietary MuTIOL interconnect that's 16 bits wide and runs at 533MHz in each direction. The interconnect yields over 1GB per second of bandwidth between the chipset's north and south bridge components, more than enough for the south bridge's integrated peripherals.

The SiS964 south bridge integrates a six-channel AC'97 audio controller, eight USB 2.0 ports, 10/100 Fast Ethernet, two ATA/133 IDE channels, and a couple of Serial ATA ports. The SiS964 also supports two-drive Serial ATA RAID 0, 1, and JBOD arrays.

The 755 chipset has what SiS calls a HyperStreaming architecture. HyperStreaming is designed to more efficiently move data within a system by splitting, prioritizing, and processing concurrent transactions over multiple links to ensure uninterrupted data transfers. The HyperStreaming architecture stretches from device-level links in the south bridge all the way through the MuTIOL interconnect and up to the north bridge, and we'll see in a moment how effectively it moves data around inside a system.