..:: Layout: Northbridge Area ::..
The SiS 655FX Northbridge is covered by a fairly large, gold plated heatsink that we have begun to see more of over the past several months on Gigabyte motherboards. The heatsink itself is also equipped with a small fan for active cooling. This cooling unit does a nice job of keeping the SiS 655FX Northbridge running cool, much better than that of the reference motherboards heatsink / fan unit that it was equipped with. When I attempted to remove the heatsink from the Northbridge, I found that it is attached via a thermal pad as we have seen several times in previous Gigabyte motherboard reviews. I’d much rather see a thermal paste used here, although given the nature of the product, there really isn’t much of a need for it. Both the 655FX and the heatsink are oriented on a forty-five degree angle to the bottom of the processor socket in order to shorten the signaling traces.
If we take a look to the left of the SiS 655FX Northbridge, we first come across the secondary, four-pin 12V ATX core voltage power supply connector. This power connector is located in the typical position that we have become accustomed to, and shouldn’t pose any real cable routing or airflow problems due to the cable size. Located just below this power connector, we come across the Realtek RTL8110S onboard Gigabit Ethernet LAN Controller chip. This positioning is somewhat unusual to what we have seen on previous motherboards, although this position is frequently utilized with motherboards that lack other PCB real-estate due to a large amount of feature integration. Just above this chip, we come across both the clock crystal for the controller, along with an Atmel AT93C46A 1K Serial EEPROM.
..:: Layout: Expansion Slot Area ::..
As usual, the next stop on our trek around the GA-8S655FX Ultra’s PCB is the expansion slot portion of the motherboard. This area is typically one of the two major zones of the motherboard where, feature-wise, things can tend to become far more packed together, whether it is due to headers, controller chips, or other miscellaneous items dealing with the motherboard feature set. The AGP slot on the GA-8S655FX Ultra is an apple green color, which conveys to the user that this motherboard supports AGP 3.0 specifications, otherwise known as AGP 8X. The slot features a pin-like retention mechanism along the front edge, and will serve the end user quite well by grasping the hooked end of the AGP card to keep it held in position.
The first items we come across are located beneath the rear I/O panel, and all address the issue of the GA-8S655FX Ultra’s onboard audio solution. Here, we find both of the typical onboard audio headers, the front panel audio header, and of course, the audio codec that powers the GA-8S655FX Ultra. As usual, I’d much prefer to see this front panel header located lower on the PCB, although given the proximity to the Realtek ALC658 audio codec, it is workable. This is the first motherboard to enter our labs featuring this new ALC658 chip, although we have already covered it in detail a few pages ago, so we won’t go into the features of this chip again.
As we move further down the PCB, we next find a single remaining item that deals with the GA-8S655FX Ultra’s onboard audio, that being the small, five-pin surround sound header. This is the header where you would need to connect the calling coming from your rear audio expansion bracket in order to utilize the various surround sound audio channels. Below this header, we find the ITE IT8705F chip. This chip is typically responsible for providing support for the older legacy devices for the system such as the serial ports, midi port, parallel port, and PS/2 keyboard and mouse ports. It also serves other functions such as support for floppy devices. Finally, when we look below the IT8705F chip, we find both the main and backup system BIOS’ that makeup Gigabyte’s “Dual BIOS” solution for their motherboard products.
The last remaining items that are located in the expansion slot vicinity of the GA-8S655FX Ultra’s PCB are a systematic layout of several onboard headers that allow for further support of features such as a midi port, if you so happen to have one that can be used via an expansion slot. Here, we also see the IR header which will allow for support of any infrared devices that the user may so wish to utilize, as long as they have the necessary cabling required. Lastly, the lone red header here is a rogue onboard audio header which couldn’t be placed near the other audio components, and it allows support for the GA-8S655FX Ultra’s digital in and out connections.