AOpen AX6BC Pro II Millenium Edition Slot-1 ATX

AOpen's jumperless CPU configuration is carried over directly from the original AX6BC and AX6BC Pro Gold. That means FSB settings of 66 / 68 / 75 / 83 / 100 / 103 / 112 / 117 / 124 / 129 / 133 / 138 / 143 / 148 / 153 are all available from the BIOS. A PCI ratio of 1/4 is available on speeds above 117 MHz. Unfortunately for AOpen, the ABIT BF6 and BE6-2 have clearly surpassed the competition in FSB flexibility with its SoftMenu III that offers FSB speeds from 83 - 200 MHz in 1 MHz increments. As we noted in that review, speeds above 124 MHz are generally not too useful since they push the AGP bus too far out of spec. The problem stems from the fact that the i440BX only features a 1:1 and 2:3 AGP ratio. This is of course a limitation of the i440BX chipset and cannot be blamed on AOpen.

A 6 pin jumper block determines the AGP ratio - options include Auto, 1/1, and 2/3. Unfortunately, the Auto setting is not as intuitive as it should be. AOpen listened to Intel's suggestion that the AGP ratio be linked to the state of BSEL, the CPU pin that determines whether a 66 or 100 MHz FSB speed should be used. This the infamous B21 pin on Slot-1 CPU's. When BSEL indicates 66MHz operation, the AGP ratio is set to 1/1 by the chipset and when BSEL says 100MHz, a 2/3 ratio is selected instead. AOpen's Auto setting links the CPU's BSEL pin to the chipset and lets it select the AGP ratio. The 1/1 and 2/3 jumper settings simply force the state of BSEL. Wouldn't it be a lot easier to just make the Auto setting automatically select 2/3 when 100MHz or higher FSB speeds are used and 1/1 otherwise? Better still would be a BIOS controlled setting.

The AX6BC Pro was the first AOpen board to offer CPU core voltage tweaks in the BIOS and the AX6BC Pro II continues the tradition. Voltage tweaks have been a boon for overclockers everywhere looking to push their CPU's to the limit as an additional 0.1V can do wonders for overclocked stability. The default detected voltage is reported in the BIOS followed by what it is currently set for. Changing the voltage from the default results in a warning message that it could damage the CPU. Once that has been bypassed, the options range from 1.3V to 3.4V. From 1.3 - 2.1V, the increments are 0.05V and then from 2.1V to 3.5V, increments are 0.1V.

Unlike some other recently updated i440BX boards, AOpen has passed up the option to upgrade the BIOS core to Award 6.00PG, sticking with version 4.60PGMA. Award 4.60PGMA is nothing more than an AOpen customized version of the classic Award 4.51PG. Like all other AOpen BIOS's, an option to load a set of "Turbo Defaults" is included to get the BIOS all tweaked up with just a couple key strokes. The user can then also save and load his/her own set of BIOS settings, allowing for experimentation without having to write down old BIOS settings. Each PCI slot can be assigned a specific IRQ for working out IRQ nightmares in a loaded system. Unfortunately, the onboard audio/video IRQ's cannot be changed nor can the USB IRQ be disabled.

One feature that is often forgotten, but included on the AX6BC Pro II, is the ability to configure what the system will do when AC power is restored after a power outage. The system can either remain off, turn on, or resume last power state when power is restored. This is a feature often overlooked since ATX and soft power became available, but is critical for anyone using their system where it must be on 24/7 or as close as possible. It also allows for users to shut the system on and off from a surge protector.