By the way, this weird behavior of the IEEE1394 controller was not the only strange thing that we discovered on our AOpen i975Xa-YDG mainboard. Besides that, the mainboard would sometimes “lose” the second memory channel and start working in a single-channel mode despite the fact that there was a pair of DDR2 SDRAM modules installed. We hope that this issue is characteristic of this particular mainboard sample only and is not a typical issue of all AOpen i975Xa-YDG mainboards. In other words, we would like to refrain from making any final conclusions yet and continue digging into the root of things here.
Besides all above listed controllers, our AOpen i975Xa-YDG mainboard also features two relatively common chips. They are PCI Express x1 Gigabit Ethernet controller from Marvell and a High Definition Audio codec from Realtek – ALC880. We won’t dwell on those two today, because we have already devoted enough time to them in the previous mainboard reviews which you can find in our Mainboards section.
The mainboard rear panel features two PS/2 ports for keyboard and mouse, six audio-jack connectors, optical SPDIF In and Out, four USB 2.0 ports, IEEE1394 port, network RJ45 connector with two diagnostic LEDs and a Serial ATA II port with the HDD power supply connector. Moreover, the mainboard also features pin-connectors for another four USB 2.0 ports, one IEEE1394 port, one serial and one parallel port and for an IrDA port.
All in all, the PCB design of AOpen i975Xa-YDG mainboard makes pretty ambiguous impression. We were quite upset about too many connectors in front of the PCI Express x16 slots, because the cables leading from these connectors may be hard to arrange inside the case and may hinder proper cooling of the graphics cards. At the same time, AOpen engineers took good care of those testers who work with the mainboards on an open stand that is outside the system case. Specifically for them there are Power On and Reset buttons in the lower left corner of the PCB that duplicate the corresponding functions usually connected to the case front panel.
The processor voltage regulator circuitry features dual-phase design and is powerful enough to serve the needs of the mobile processors consuming very little power. They use a four-pin connector to tie up the voltage regulator with the power supply unit. The voltage regulator itself is built with very high-quality Rubycon capacitors that gives us some hope that this mainboard is going to serve its purpose for a long time without failure.
You can also find one more MOLEX power connector between the PCI Express x16 slots and the processor voltage regulator. This connector is used to power the Serial ATA hard disk drives connected to the external port as well as for additional powering of the PCI Express x16 slots when there are two graphics cards in the system.