SiS 655FX Chipset - Page 3

..:: SiS 655FX Reference Motherboard ::..

Due to the fact that the motherboard we received from SiS is in fact a reference design and not something you would see in the retail market, we will not be taking our usual in depth look over of the PCB design. I would, however, like to quickly go over some of the aspects of the reference motherboard for those of you whom might not have ever seen a reference motherboard before. They are quite interesting pieces, good wall mounting material I say. SiS has a tendency to elongate their reference designs just enough so that they will not fit in a normal motherboard housing, and the 655FX reference board does not fail to disappoint when it comes to this aspect. If you look along the bottom edge of the board, youíll notice that there is a large connector actually built into the motherboard PCB itself. This is likely used for mass testing and validation purposes by the engineers within SiS when they are testing the chipset and motherboard for stability, and all other important aspects that go into this process.

As far as design goes, the top portion of the motherboard looks like your typical PCB design. The processor socket is oriented lengthwise from north to south with the CPU fan three-pin power connector located towards the upper right corner of the retention mechanism. To the left, we come across all of the core components of the three-phase core voltage power supply for the motherboard. This board is powered by the more advanced Intersil 6556BCB chip for those interested parties out there. Below the processor socket, we, of course, come across the 655FX Northbridge itself which is outfitted with a small heatsink / fan unit. This unit itself is attached to the Northbridge via a large thermal pad which should allow good enough cooling for some overclocking of the board.

The DIMMís are setup in your typical dual channel fashion, with each channel being given a color to signify the differences, in this case red and black. The only item that many of you may think of as missing from this portion of the board is, of course, the main 12V ATX power connector. Well, this connector is actually located quite a ways down the board in the area where you would typically find your PCI slots. The expansion slot portion of the board also houses some pretty unique aspects of the reference motherboard. Here we see that there is a single AGPO 4X/8X slot, followed by a very small AMR slot. Below these, we find the 12V ATX power connector, two PCI slots, and oddly enough, all of the extra audio connectors and features that are offered by the reference board. This is certainly the most unique place that I have ever seen these located.

The bottom right hand portion of the motherboard around the 964 Southbridge houses the remainder of the items needed by the 655FX reference motherboard. Here we come across the typical ATA/133 connectors, and the floppy connector. The BIOS that is used by the motherboard runs horizontally along the bottom edge of the PCB, where we also find the little red and black power and reset buttons. Iíve always been a fan of these buttons as they make life much easier, well, in reviewing circumstances they can be a dream come true. This area also houses both of the SATA connectors that are supported by the 964 Southbridge. Youíll also notice that there are quite a large amount of jumpers, and headers located throughout this portion of the board. These are responsible for the various voltages supplied to the chipset, processor, etc. As you can see, this motherboard design does not follow your typical retail one, but it certainly is interesting to see now and again.