SiS 648 Chipset Debuts

The SiS 648 Chipset Debuts - Page 1

The SiS 648 Chipset Debuts
A Comprehensive Look at a Pre-Production Shuttle AS45GT/R

By, Marco Chiappetta
August 12, 2002


In early 2002 Silicon Integrated Systems Corp. (SiS) released their 645 chipset.  Initially, many analysts were skeptical that SiS could deliver a high-performing DDR chipset for the Pentium 4.  They were all quickly proven wrong though, as time and again the SiS645 performed at, or near, the top of the pack in review after review.  Looking to build upon the relative success of the 645, SiS took the wraps off of their latest chipset for the Pentium 4, the 648.  With the new 648 Northbridge, SiS is also releasing their new 963 Southbridge which incorporates a host of options that make it one of the most feature-rich products available to date.

Shuttle Computer Group was the first manufacturer to supply us with a pre-production motherboard based on the SiS648 for testing.  Today we'll be taking a look at Shuttle's AS45GT/R, and comparing it's performance against an i850E based motherboard from Asus, the P4T533.  First we'll cover some of the new features incorporated into the 648, and then we'll explorer the AS45GT/R's features and performance...

Specifications / Features of the Shuttle AS45GT/R (SiS 648)
Lots of Goodies...




  • Socket 478

  • Intel Pentium 4 / Celeron in the 478 pin package with 400/533MHz FSB


  • (North) SiS 648

  • Supports Intel R Pentium R 4 processor system bus at 100/133 MHz

  • (400/533 MHz Data Bus)

  • 3 Un-buffered DIMM of 2.5 volt DDR200/266/333 compliant SDRAM up to 3 GB memory capacity

  • AGP interface to support external AGP2.0 / 3.0 compliant device

  • High Throughput SiS MuTIOL connect to SiS963 MuTIOL Media I/O to perform 1GB/s bandwidth

  • (South) SiS963

  • Support UDMA 33/66/100/133 IDE interface

  • Integrated 2 USB 1.1/2.0 compliant host controller to support up to 6

  • USB ports

  • Built in Integrated LAN MAC

  • Built in 1394 controller

  • Support ACPI 1.0b compliant power management

  • Built in RTC (Real Time Clock)

  • PCI interface supports PCI 2.2 compliant device

  • Front Side Bus - 400/533MHz

Expansion Slot:

  • 1 x AGP 2.0 / 3.0 compliant slot

  • Support external AGP V2.0 / 3.0 compliant VGA device

  • Support 2X, 4X, 8X AGP data transfer

  • Support external 1.5V AGP electrical device

  • Integrated AGP-proof circuit to prevent the electrical damage by 3.3V AGP card

  • 5 x PCI slots

  • PCI 2.2 compliant, 32-bit BUS Master Slots

  • 133 Mbyte / sec maximum throughput


  • 3 x 184-pin DDR SDRAM

  • Supports 6 banks up to 3 GB PC1600/2100/2700 compliant DDR SDRAM

H/W Audio:

  • 6 channel audio

  • Realtek ALC650 on board

  • 18-bit ADC and DAC resolution

  • Compliant with AC?97 2.2 specifications

  • 6 channel slot selectable DAC output for multi-channel applications

  • 3D Stereo enhancement

  • Digital S/PDIF output.

  • Digital S/PDIF input.

IDE interface:

  • On board High Point 372 (AS45GTR only)

  • 2 x UltraDMA100 / 133 Bus Master IDE from SiS963

  • 2 x UltraDMA100 / 133 Bus Master IDE from High Point 372 to support RAID 0, RAID1, RAID0+1 function

  • 80-pin Cable Backward Compatible Legacy ATAPI Devices

  • ATAPI IDE CD-ROM, CD-R, CD-RW, and LS-120 Supports

Serial ATA interface:

  • On board Marvell 88i8030 (AS45GTR only)

  • Support serial ATA interface of 1.5Gb/s bandwidth

  • 2 x Serial ATA connectors from Marvell 88i8030 to support RAID 0, RAID1 function

1394 interface:

  • Built in SiS 963

  • Compliant with IEEE 1394-1995 and 1394a-2000

  • Provide Bus Master function Interface (OHCI) Specification1.1.

  • Supports the Plug-and-Play (PNP) Specification.

  • Compliant to Latest PCI Specification, PCI 2.2.

  • Supports Serial Bus Data Rates of 100, 200,and 400 Mbits/s.


  • ITE 8705F

  • Comply with Intel Low Pin Count Interface Specification Rev. 1.0

  • ACPI V. 1.0 compliant

  • Built in H/W monitor feature

  • Two 16C550 UARTs

  • Supports two standard Serial Ports

  • Supports IrDA 1.0/ASKIR protocols

  • Supports Smart Card Reader protocols

  • Built in Smart Card Reader

  • IEEE 1284 Parallel Port

  • Standard mode -- Bi-directional SPP compliant

  • Enhanced mode -- EPP V. 1.7 and V. 1.9 compliant

  • High speed mode -- ECP, IEEE 1284 compliant

  • Floppy Disk Controller - Supports two 360K/ 720K/ 1.2M/ 1.44M/ 2.88M floppy disk drives

  • Enhanced digital data separator

  • 3-Mode drives supported

  • Support power-failure resume and power button de-bounce

USB 2.0 interface:

  • Built in SiS 963

  • Complies with Universal Serial Bus Specification Rev. 2.0

  • Complies with Enhanced Host Controller Interface Specification for USB

  • High performance USB 2.0 host with integrated USB 2.0 transceiver, which supports high-speed, full-speed and low-speed signaling

H/W Monitoring:

  • Built in ITE 8705F

  • 2 thermal inputs from remote thermal resistor to monitor system temperature

  • 1 thermal inputs from thermal diode to monitor CPU temperature

  • 8 voltage monitor inputs

  • 1 chassis intrusion input

  • Monitors 3 fan tachometer inputs

  • Smart Guardian Controller to provide programmable fan speed automatic control

Power Management:

  • APM 1.2 compliant

  • ACPI 1.0 compliant

  • Support multiple system suspend types- suspend to DRAM, suspend to disk, and all with hardware automatic wake-up


  • Award PnP BIOS

  • Stored in 2 Mb flash memory

  • DMI 2.3

  • CPU 100 / 133MHz FSB setting

  • BIOS FSB step-less setting from 100MHz to 200MHz with 1 MHz increment

  • CPU core voltage setting from +0.025V ~ +0.20V

  • AGP (Vddq) voltage setting from +0.05V ~ +0.20V

  • I/O voltage setting from +0.1V ~0.2V

  • Support IRQ manual assign table

  • Bootable from Floppy, ATAPI device, USB device, SCSI device

On Board Ports / Connectors / Jumpers / Headers (front/back panel):

  • Back Panel:

  • 2 Serial Ports

  • 1 Parallel Port (SPP, EPP, ECP)

  • 1 PS/2 Keyboard Port

  • 1 PS/2 Mouse Port

  • 2 USB Ports

  • 1x Game / MIDI Port

  • 1x Line in

  • 1x Line out

  • 1x Mic


  • 1 x ATX power connector

  • 1 x 4 pin 12V ATX power connector

  • 4 x Fan Power connectors

  • 2 x UltraDMA/133 Bus Master IDE (4 IDE AS45GTR optional)

  • 2 x Serial ATA (AS45GTR only)

  • 1 x Floppy


  • Clear CMOS

  • BIOS Boot block protection


  • 2 sets of 2 x5 pin Front Panel USB header

  • 1 x Central / Base audio header

  • SPDIF IN / Out

  • Mini CD Audio in

  • TAD in

  • CD Audio in

  • 3 X 1394 ports

  • Other Features:

  • Suspend switch and LED


  • CD-ROM Disk

  • SIS IDE Driver

  • SIS AGP driver

  • Realtek Audio driver

  • ITE Smart Guardian Utility

  • High Point IDE driver (AS45GTR only)

  • User manuals in PDF format

  • 1 x audio cable for center / Bass output

  • 1 x USB cable with bracket

  • 1 x ATA 133/100/66 cable

  • 1 x ATA 133/100/66 cable (AS45GTR only)

  • 1 x Floppy cable

  • 1 printed user manual

  • Chipset heat sink with fan, CPU RM, AGP RM

Form Factor:

  • ATX


With the 648, SiS has taken all of the features found in the 645 chipset, and added quite a few more, making the 648 the most feature-rich chipset currently available.  The main enhancements over the 645 include:

  • AGP8X (3.0)

  • Official Pentium 4B 533MHz FSB support

  • Official DDR333 Support (unofficial DDR400 support)

  • USB 2.0

  • IEEE-1394

  • MuTIOL 1G (I/O Interconnect)

  • 10/100 LAN

  • 6-Channel AC'97 Audio

  • ATA/133 EIDE Interface

While the addition of USB 2.0, 10/100 LAN and ATA/133 should be expected in any "new" chipset, some of other items are worth talking about.  AGP8X effectively doubles available bandwidth to the AGP bus, bringing the total up to 2.1GBs per second.  This doesn't mean much, if anything today, but when with high-end video cards like ATi's Radeon 9700 and NVIDIA's NV30 begin shipping, and newer games start making use of more polys and larger textures, having the extra bandwidth available should have a measurable affect of performance.

DDR333 (166MHz) and DDR400 (200MHz) memory speeds increase available memory bandwidth to 2.7GBs/Sec and 3.2GBs/Sec respectively, which brings the P4 with DDR incrementally closer to the performance levels of an RDRAM based system.  As you'll see in our benchmarks a little later, the SiS648 turned out to be an excellent performer.

The MuTIOL 1G connection between the North and South bridges is another bandwidth increasing feature.  SiS' latest version of their proprietary MuTIOL interconnect offers a maximum of 1GB per second of bandwidth between the SiS648 Northbridge and SiS963 Southbridge.



Included in the Shuttle AS45GT/R's box we found a user's manual, and a manual for the on-board High-Point HPT372 RAID controller.  There were two 80-Wire UDMA/133 cables, a floppy cable and another you may not have seen before, a Serial ATA cable.  There was also a CD containing all of the necessary drivers for the board, and two brackets for external connectors, one with two USB ports and the other with two IEEE-1394 ports.

Installation and Setup
Good supporting hardware is essential

Quality RAM Makes A Difference - We recommend Corsair


We did not have do anything out of the ordinary to get the SiS648 based Shuttle AS45GT/R installed into our test machine, other than installing the SiS AGP and IDE drivers once Windows was up and running.  There is something that you have to keep in mind though.  Reliably running a system at high FSB or Memory speeds requires the use of quality RAM.  When we initially began testing the Shuttle AS45GT/R, our test system repeatedly locked-up, or re-booted for no apparent reason.  We suspected the RAM we were using was not stable at 200MHz, so we contacted Corsair Micro and got our hands on a quality, 512MB stick of PC3200 DDR RAM. (Product specs can be found here)  If you're familiar with Corsair, you know their memory is held in high regard.   Should you be in the market for some new memory, you owe it to yourself to check their product out.

The BIOS, Layout and Quality 


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

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