The Pro variants in the AOpen motherboard line add a few enhancements over the standard version, among them voltage controls, a 24K gold chipset heatsink and additional capacitors. While the first two are nice features, the extra capacitors have been arranged neatly around the FC-PGA socket like soldiers protecting their turf. While this arrangement does not interfere with standard CPU coolers, larger heatsinks like our reference Athlon Freezer device would not fit, but actually sat right on top of the capacitors. The FC-PGA socket has an angled retention arm, but it sits low enough on the base to not hamper installation of slightly larger heatsinks.

The AX3S Pro also has three on-board fan headers, which allows a full complement of case cooling options. Placement of the fan headers is excellent and if your CPU cooler requires dual headers, the back-mounted case fan header is easily accessible. The ATX power connector is situated right between the DIMM sockets and the FC-PGA CPU socket, ensuring CPU airflow is unaffected, but possibly interfering with both CPU and memory installation. While this is not the optimal location for the ATX connector, it is still much better than having the ATX power cord go overtop of the FC-PGA socket and motherboard chipset.

The placement of the floppy connector is standard issue, but the IDE connectors have been shifted down below the DIMM sockets. These two IDE connectors are also perpendicular to the floppy DIMM ports and parallel to the second PCI slot. This definitely brings up some possible installation issues, especially with full-length PCI cards used in PCI slot 1. Even the AGP card may come into contact or interfere with the IDE cable, especially those coming from 5.25” IDE devices that sit much higher in the PC case.

The AX3S Pro features the usual i815E arrangement of jumpers that determine the initial FSB (front-side bus) speed and AGP/PCI dividers. The AX3S Pro allows the full gamut of CPU choices including CPU auto-detect, 66, 100 and 133 MHz settings. The jumpers are located at the top of the board, beside the DIMM sockets. The positioning of these jumpers is also very good and there is enough open real estate to allow you to reach in and adjust them by hand if necessary.

The board's ATX backplate is standard design for the i815E, featuring two USB, one serial, one VGA-out, LPT, and two PS/2 ports, along with the usual game and audio connectors. AOpen also includes an adapter for the second serial port, but not for the second pair of USB ports. The ATX front panel connector is a standard layout, and has been placed at the very bottom of the board, well out of the way of the PCI slots. There are also on-board connectors for CD-in, Modem-In and Video Audio-In, as well as for Wake on LAN (WOL) and Wake on Modem. The AX3S Pro has a pin-out for the optional Dr. LED, a display that fits in an open 5.25” bay and serves to diagnose boot-up problems similar to the MSI D-LED feature.

Including some sort of BIOS protection is becoming a very popular feature on motherboards. AOpen follows this trend with their Die-Hard BIOS, which consists of a secondary rescue ROM that cannot be written to. This solution is not as seamless as Gigabyte's DualBIOS, and in the event of a BIOS problem, the PC case will need to be opened to manually change a jumper. Still, this format is better than no BIOS protection at all, especially since BIOS failures are very few and far between.