• SiS661FX chipset (SiS648FX with SiS Mirage graphics core)

The company launched a model quite typical for its "standard" series: inexpensive miniature mainboard with integrated video and modern minimum of functionality. It's a rather exotic chipset, but in time it will be as successful as SiS650/651.

It's difficult to expect a convenient PCB layout from a mainboard of the mATX form factor. But when its dimensions are reduced even relative to this standard, all possible troubles come into force. As a result, various connectors are located too close to each other so that you'll have to unplug some connectors to plug the others or even to remove the mainboard from its case. But when assembled, this mainboard will pose no problems to you. On the other hand, access to the only jumper (to clear CMOS) is not hampered even when the mainboard is installed into a case. A short description of the jumper is provided on the PCB. The 2-phase switching voltage regulator of the processor incorporates twelve 1500 uF capacitors, field-effect transistors in this circuit are covered with small heatsinks to improve the thermal conditions. The mainboard also contains voltage regulators for AGP (two 1000 uF capacitors) and memory (two 1000 uF capacitors).

The only difference of Revision C of the mainboard from its predecessor is in the redesigned CPU feed circuit. As a result, this revision allows processors based on Prescott core. In fact, the PCB used in 661FX-MLV also serves a base for the 661FX-MLVE mainboard, which incorporates the "lite" SiS964L southbridge without SATA support. The mainboard lacks the following elements, which locations are provided by the PCB layout: a connector for back speakers and a subwoofer, and a third fan connector. Mainboard dimensions – 245x200 mm ("narrowed" mATX, six-screw mount, the fore PCB edge may sag). The ITE IT8707F chip is used to monitor:

• CPU voltage, +3.3, +5 and +12 V
• RPM of 2 fans
• CPU and board temperatures (by the corresponding embedded sensors)

Onboard ports, sockets, and connectors

• CPU socket (Socket 478, mainboard revision C supports processors based on Prescott core)
• 2 x DDR SDRAM DIMM (up to 2 GB DDR200/266/333/400)
• 1 x AGP (with a latch)
• 3 x PCI
• Power connectors: standard ATX and 4-pin connector for 12 V
• 1 x FDD
• 2 x IDE (Parallel ATA) – all in the chipset
• 2 x SATA (Serial ATA) RAID – both are in the chipset, supporting RAID 0, 1 and JBOD
• 2 connectors for brackets with additional USB (2.0) ports
• 1 x CD/DVD audio connector
• Headers for additional Audio-Outs and S/PDIF
• 2 x fan connectors (both with RPM control)

Back panel (left to right, blockwise)

• PS/2 mouse and keyboard
• 1 LPT, 1 COM port, 1 D-Sub (VGA)
• 2 x USB
• 2 x USB and 1 x RJ-45 (Fast Ethernet)
• 3 x Audio (Mic-In, Line-In, Front)

Package Contents

• Standard design box
• Documentation: Short user's guide in 4 languages
• Cables: 1 x SATA, 1 x ATA66/100/133, and an FDD cable
• Back PCB panel bracket for corresponding connectors
• Floppy with SATA RAID drivers
• CD with software:
  • mainboard drivers
  • user's guide in PDF format
  • Adobe Acrobat Reader
  • DirectX 8.1

Integrated Controllers

• AC'97 Avance Logic ALC655 Audio Codec supporting 5.1 surround sound audio, with front line-in/out and S/PDIF jacks
• LAN, based on the chipset and the Realtek RTL8201BL PHY controller supporting 10/100 Mbit/sec Base-T (Fast Ethernet)

The integrated audio quality was tested in 16bit, 44 kHz using the RightMark Audio Analyzer 5.2 test application and the Terratec DMX 6fire sound card:

General performance: Good (details). Typical quality of integrated audio is provided by Avance Logic codec in a cheap mainboard – this is maximum you can expect from a budget model.

Settings

We used BIOS dated 26.05.2004, the latest available BIOS version at the time of our tests. The mentioned BIOS parameters are available in this version, but the viability of non-standard settings hasn't been tested.

The mainboard page on the official site of the manufacturer (Russian mirror)

Dmitry Majorov (destrax@ixbt.com) 20 August, 2004

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