A Closer Look at SiS 655TX

While AnandTech was impressed with the features and value of the earlier Gigabyte 655FX, the performance found was nothing to write home about. So what has SiS changed in the 655TX incarnation to improve performance?


The most significant performance improvement in the 655TX is the reduction in latency by removing half the command cycles from the communication between the CPU and memory. SiS claims that this brings memory performance to 865/875 levels, which would be significant indeed since the Intel memory controller is a very good performer for a chipset-based controller.



Other features of the 655TX are very close to the 655FX, but they are refined to be more competitive with current and upcoming Intel chipsets. The 655TX is also paired with the 964 South Bridge to offer SATA RAID and 8 USB 2.0 ports for a very contemporary feature set.

Full Prescott Compatibility

655TX also fully supports FMB (Flexible Motherboard) 2.0 and VRM (Voltage Regulator Module) 10.0 specifications. This means full compatibility with upcoming Prescott processors. Both the Asus and Gigabyte manuals list Socket 478 Prescott processors as fully supported on their 655TX motherboards. Since there has been so much confusion and misinformation on the web about the new specifications, the FMB and VRM tables should help in better understanding what is required and the features provided in the new standards.

 FMB 1, 1.5, 2.0
 CPU Code Support  FMB 1  FMB 1.5  FMB 2
Willamette VRM9.0 60A
Northwood VRD10 60A 70A
Prescott VRD10 78A 91A 119A VRD10.1

 VRM 10.0 VS VRM 9.0
   VRM 10.0  VRM 9.0  Benefit of VRM 10.0
VID 6 bit 5 bit More accurate voltage adjustment
0.0125V 0.025V
Voltage Range 0.8375 - 1.6 1.1 - 1.85 Lower voltage
  • Northwood and Prescott dual support
  • Supports higher frequency CPU
  • Dynamic VID Yes No Supports CPU that can change Voltage on the Fly

    SiS655TX Specifications

    Advanced HyperStreaming™ Engine
  • SiS HyperStreaming™ Technology allows streams of chipset data to flow over all paths efficiently, concurrently, smoothly and intelligently. The SiS655TX Advanced HyperStreaming™ Engine further enhances the transfer rate on the path from host block to memory controller block to achieve lower latency that can improve whole system performance.


  • Host Interface
  • Support Intel Pentium® 4 HT FSB 800 CPU
  • Support Intel Hyper-Threading Technology
  • Support 800/533/400MHz Front-Side Bus


  • High Performance Dual DDR 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 Rev.3.5 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
    LPC 1.1 Interface
    Integrated RTC
    Integrated Keyboard/PS2 Mouse Controller

    Index Basic Features: Asus P4S800D-E vs. Gigabyte 8S655TX Ultra
    POST A COMMENT

    24 Comments

    View All Comments

    • WhoBeDaPlaya - Friday, April 23, 2004 - link

      LOL swt - wish I got paid for the reviews I write :P Reply
    • swt - Saturday, February 7, 2004 - link

      Having bought the P4S800E, I can correct a couple of misimpressions.

      First, the passive heatsink on the NB isn't so large as to interfere with my Zalman CNPS-7000Cu. Other mondo coolers might be problematic, of course.

      And the AMI BIOS now supports multiple CPU Core settings, all the way up to 1.9V. Since I don't get paid to write such reviews, I'm not going to type in the details - but the BIOS that shipped with the MB *has* been updated in that regard, as promised.
      Reply
    • buzzby311 - Tuesday, December 30, 2003 - link

      Reply
    • buzzby311 - Tuesday, December 30, 2003 - link

      All of the current memory reviews talk about memory that is great for the 865 875 chipsets. What memory would be good for overclocking on this motherboard with an Intel 3.0GHz 800FSB HT processor? Reply
    • Wesley Fink - Monday, December 15, 2003 - link

      Asus says the P4S800D-E will appear on their web site on Friday, December 19, 2003. They expect the boards to be available for sale in the US by January 1. Reply
    • ColdRolledSteel - Thursday, December 11, 2003 - link

      I also would like to know when the P4S800D-E is coming out. It isn't listed anywhere, including on the usa.asus.com website.... Reply
    • Wesley Fink - Wednesday, December 10, 2003 - link

      Spacecomber -

      We normally check FSB and report those that are out of spec. With these 3 boards all are within 0.5MHz of 200. The Asus P4S800D-E is 200.1, and both Gigabyte 8S655TX Ultra and Asus P4C800-E are at 200.5. If numbers are way off we correct them to 200 (800) before running benchmarks if possible.
      Reply
    • Spacecomber - Wednesday, December 10, 2003 - link

      Unless I missed it, did you check to make sure no one was cheating a bit with their front side bus speed? Is a 200 MHz frontside bus really a 200 MHz frontside bus for all three boards that you compared?

      Thx

      Space
      Reply
    • Wesley Fink - Wednesday, December 10, 2003 - link

      #14 - All our Benchmark tests on the 655TX boards were done with an ATI 9800 PRO with Fast Writes enabled, so there does not not seem to be a general problem with ATI cards. Reply
    • valnar - Wednesday, December 10, 2003 - link

      #3
      Why would I want to give up that?
      Reply

    Log in

    Don't have an account? Sign up now