SiS 655FX Chipset

Introducing the 655FX Chipset from SiS - Page 1


Intoducing the SiS655FX Chipset
An Overview of Functionality and Performance

By: Jeff Bouton
October 2, 2003

By now you all know the drill, Intel or AMD release a new chipset for their processor platform and the other third party manufacturers, like VIA, NVIDIA, ALi, and SiS, are soon to follow.  This time around we are talking about the latest release from Silicon Integrated Systems, with their SiS655FX chipset.  Their latest incarnation is a potent package, challenging the Intel 865/875 family chipsets in an effort to offer some competition in both price points and features.  SiS introduced several new features to give the SiS655FX an edge over the competition, with the most important being the introduction of HyperStreaming.  By maximizing bus bandwidth between the Northbridge and Southbridge, SiS aims to improve performance by reducing any bottlenecks between the two chips.  This will allow for better communication and should result in an improvement with data transfer, that can be evident in hard drive performance and other IO performance.

Recently we were presented with a reference motherboard from SiS to give us a taste of what the SiS655FX was capable of.  So let's get things started by getting acquainted with what the SiS655FX has to offer, then we'll size it up against an Intel 865PE based motherboard, to see how the latest from SiS stacks up.

Features of the SiS 655FX Chipset
Features and Functionality


SiS655FX w/SiiS964

  • Host Interface Controller
    - Support Intel Pentium® 4 HT FSB 800 CPU
    - Support Intel Hyper-Threading Technology
    - Support 800/533/400MHz Front-Side Bus
  • Integrated High Performance Dual Memory Controller
    - Delivering up to 6.4GB/s Bandwidth
    - Performance optimization auto-configurability with flexible granularity via supporting the Dual 128x1 bit mode in symmetric DIMM types
    deployment, and the Concurrent Dual 64x2 bit mode with flexible DIMM
    types support
    - Up to 4 DIMMs of DDR400/DDR333
    - Support Un-buffered DDR DIMM and up to 1GB per DIMM
    - Suspend-to-RAM(STR)
  • Support AGP 8X Interface
    - Support AGP 8X/4X Interface
    - Support Enhancements of AGP v3.5 Register Format
    - Support Fast Write Transaction
  • MuTIOL 1G® Delivering 1GB/s Bandwidth
    - Proprietary Interconnect between SiS655FX and SiS964
    - Bi-Directional 16-bit Data Bus at 533MHz Operating Frequency

SiS964 MuTIOL 1G® Media I/O

  • MuTIOL 1G® Delivering 1GB/s Bandwidth
    - Proprietary Interconnect between SiS655FX and SiS964
    - Bi-Directional 16-bit Data Bus at 533MHz Operating Frequency
  • USB 2.0/1.1 Host Controller
    - One EHCI USB 2.0 Controller and three OHCI USB 1.1 Controllers
    - Support Total 8 USB 2.0/1.1 Ports
    - Support USB 2.0 High-Speed Device @480 Mb/s Transfer Rates
  • Serial ATA Host Controller
    - Two independent ports and flexible channel allocation
    - Compliant with Serial ATA 1.0 Specification
    - Support Ultra DMA 150
    - Support RAID 0, RAID 1 and JBOD configuration
  • PCI 2.3 Specification Compliance
    - Support up to 6 PCI Masters
  • Fast Ethernet/Home Networking Controller with MII Interface
    - Support 10/100Mb Fast Ethernet or 1/10Mb HomePNA 2.0 with External PHY
  • Audio/Modem Controllers with AC?97 Interface
    - AC?97 v2.3 Compliant
    - Support 6 Channels of AC?97 Speakers Out and v.90 HSP Modem
  • Advanced Power Management
    - ACPI 2.0 and APM 1.2 Compliant
  • Dual IDE Channels with Parallel ATA 133/100/66
  • LPC 1.1 Interface
  • Integrated RTC
  • Integrated Keyboard/PS2 Mouse Controller
  • PC2001 Compliant


The latest SiS Chipset is a combination of two components, the SiS655FX Northbridge and the SiS964 Southbridge.  The 655FX Northbridge handles all of the CPU and Memory functions as well as AGP processes.  The Northbridge has been updated with a dual DDR400 memory controller, for a maximum bandwidth of 6.4GBs per second.  This kind of bandwidth should be more than sufficient to insure that there is no bottleneck, between the memory access and the Intel's Quad Pumped Processor bus, which is supported up to 800MHz for the most recent Northwood cores.  Each memory slot can support up to 1GB DIMMs, totaling 4GBs. 

Click to Enlarge


The Southbridge handles all of the peripheral functions, such as providing integrated 10/100 LAN, Dual IDE and SATA channels, and 8 USB 2.0 ports to name a few.  The North and Southbridge are connected Bi-directionally at 533MHz yielding an effective bandwidth of 1GB/s.  Dubbed "HyperStreaming", this higher bandwidth ensures smoother operation of peripheral components as the communication between the North and Southbridge is optimized.  The most obvious improvement in performance should be found with data transfer and hard drive performance.



The Reference Board and Test System


Tags:  Chipset, Chip, chips, SIS, fx, IPS, IP

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