AOpen MX64 VIA Apollo Pro 133A Slot-1 microATX

AOpen's jumperless CPU configuration is carried over almost directly from the Apollo Pro 133 based AX63Pro. Like that model, the MX64 features the Award 4.60PGA BIOS core, which is a custom AOpen version of the more common 4.51PG. Now that Award has the improved 6.00PG, we'd like to see all manufacturers go ahead and implement it on their boards. FSB settings of 66 / 75 / 83 / 100 / 105 / 110 / 112 / 115 / 120 / 124 / 133 / 140 / 150 are all available in the BIOS, as are clock multiplier settings. While there are 7 FSB speeds between 100 and 124 MHz, we'd like to see more in the 133 - 150 MHz range, especially with the incredible overclocking ability of the Coppermine core.

The non-jumperless part of the setup comes when you want to overclock. Two 6-pin jumper blocks determine what frequency range is available in the BIOS, with the option of Auto, 66-83 MHz, 100-124MHz, and 133-150MHz. The Auto setting of course determines what range of frequencies are available based on the CPU in use and its default speed. The other settings are, of course, intended for overclockers. All AGP and PCI ratios are automatically handled based on the FSB speed range selected via the jumpers or auto detected from the CPU.

Unfortunately, the part that was lost from the AX63Pro is core voltage manipulation in the BIOS. This feature has been a boon to overclockers everywhere where that extra bit of voltage can often mean the difference between 100% stability and complete failure.

Once again, we were able to push our testbed FC-PGA Pentium III 550E to 5.5 x 150 MHz = 825 MHz - faster than any production level Intel CPU at the time of publication. No core voltage adjustments were necessary for our CPU. For full details, read Part 1 and Part 2 of AnandTech's Overclocking the FC-PGA Coppermine article. At overclocked or non-overclocked speeds, the MX64 was rock solid, as we've come to expect from AOpen.

Like other Apollo Pro 133/133A boards, the MX64 supports an "asynchronous" memory clock, meaning that it can run at a different speed than the FSB. Options include FSB clock and FSB clock +/- 33 MHz. When using the 133 MHz bus, FSB + 33 MHz is not available, nor is FSB - 33MHz when using a 66MHz FSB. It should also be noted that the setting labeled +/- 33 MHz is actually adding or subtracting the PCI bus speed. So if you're running a 150 MHz FSB, with the memory clock set for FSB - 33 MHz, you're actually getting 150 - 37.5 = 112.5 MHz (FSB = 150 MHz, PCI clock = 150/4=37.5 MHz). This is also a function of the VIA chipset rather than something unique to AOpen.

The BIOS options may come as a bit of a surprise for those that have never used a VIA based board before, as there are a number of options not found on Intel chipset-based systems. The most obvious is the memory setting mentioned above. As with other VIA Apollo Pro 133A boards, the AOpen offers the ability to enable or disable AGP 4X support from the Chipset Features Setup. Interestingly enough, there was no option for enabling/disabling AGP Fast Writes.

With the Tyan Trinity 400, we ran into some AGP 4X compatibility issues, but things went more smoothly with the AOpen. The NVIDIA GeForce and NVIDIA TNT2 Ultra ran without a hitch in AGP 4X mode. Unfortunately, the ATI Rage Fury MAXX still locked up upon initialization of the Windows GUI when set for AGP 4X operation. Once again, setting the BIOS option to AGP 2X remedied the problem. It's hard to say right now whether this is a hardware issue or something that can be fixed with a BIOS/driver update. However, we'll be sure to keep you updated as we have more time with the boards and find out more information.

One feature that is included, but is still missing on some motherboards, 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.

The VIA 686A Super South Bridge provides support for integrated hardware monitoring of 5 positive voltages, 3 temperatures, and 2 fan speeds. AOpen chose to monitor only 4 voltages, including Vcore, +12V, +5V, and +3.3V. Temperature is read from the CPU's on-die thermal diode, the 686A chip itself, and from a thermistor header placed next to the DIMM slots. Unfortunately no such thermistor is included with the board. One fan header is located next to the CPU, while the other is at the front left corner of the board. No hardware monitoring information is shown in the BIOS, but can be read by the included utility or by many of the shareware utilities available on the web.