Intel i815 / i815E Motherboard Roundup - August 2000

AOpen AX3S Pro

AOpen AX3S Pro
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CPU Interface	Socket-370
Chipset	Intel i815E
Form Factor	ATX
Bus Speeds	66 / 68 / 75 / 78 / 80 / 95 / 100 / 105 / 110 / 114 117 / 122 / 127 / 129 / 133 / 138 / 140 / 144 146 / 150 / 157 / 160 / 166
Voltages Supported	1.30 - 2.05V (in 0.05V increments) 2.10 - 3.5V (in 0.10V increments)
Memory Slots	3 168-pin DIMM Slots
Expansion Slots	1 AGP Slot 5 PCI Slots (4 Full Length) 1 CNR Slots (Shared) 0 ISA Slots
Onboard Audio	Analog Devices AD1885 AC'97 CODEC
BIOS	Award Modular BIOS 6.00PG AOpen Die Hard BIOS

The AOpen AX3S Pro is the latest in AOpen's "Pro" line of motherboards. The "Pro" line began with the AX6BC Pro Gold, an i440BX board, and have since included 24K gold plated heatsinks, CPU core voltage adjustments, low ESR capacitors, and now AOpen's Die Hard BIOS.

In the past, these features have combined to produce rock solid motherboards, resulting in a couple of AnandTech Editor's Choice Gold Awards. Unfortunately, the AX3S Pro was not quite as stable as past AOpen boards that have made their way through the AnandTech labs. At CAS 2 / 133 MHz, the AX3S Pro could not even complete POST (Power On Self Test). Dropping back to CAS 3/133 MHz resulted in a very solid motherboard. This is the second board in this roundup that we've looked at so far, and the second board with this problem. Fortunately for us, but not so for AOpen and ABIT, the majority of the boards did not exhibit this behavior.

This time around, AOpen has implemented Award's Modular BIOS 6.00PG on a mainstream board. Unfortunately, their jumperless CPU setup is a bit confusing. Often you'll see the same FSB setting listed multiple times in the CPU setup. Selecting these different copies of the "same" FSB speed, you can see that the difference between them lies in the Spread Spectrum setting and the SDRAM/PCI clock. If this sounds a bit confusing to you, you're not alone by any means. A much better solution would be to list the Spread Spectrum, SDRAM, and PCI clock along with the FSB speed. Another even better option is to make these settings separate from the FSB selection. As it stands, this is definitely one of our biggest complaints about the AX3S Pro, but one that can hopefully be fixed with a future BIOS update.

AOpen boards continue to not be 100% jumperless - you've got to use jumpers to set the AGP ratio. It basically works by tricking the motherboard into thinking you have a faster default FSB than you really do for overclocking purposes. The jumpers can be set to auto in which case the board will detect what FSB settings and AGP clock ratio to enable based on the type of CPU is installed. The only time you'll need to touch these jumpers is if you plan to overclock your CPU and need a different AGP ratio as a result of a significantly higher FSB speed.

To aid in your overclocking adventures, AOpen once again offers CPU core voltage adjustments on the AX3S Pro. However, this time around they're completely unrestricted from 1.30-3.50V, so make sure you don't fry your CPU by choosing an entirely too high voltage.

Like Gigabyte's DualBIOS, AOpen's Die Hard BIOS will prevent you from ending up with a corrupted BIOS by providing a backup of the BIOS. A jumper determines which BIOS will be used to boot the system, which means that you'll need to open your case to make this change if it becomes necessary. Fortunately, that shouldn't be too often.

A non-Pro version of the AX3S is also available, but without the gold-plated heatsink, CPU core voltage tweaks, and low ESR capacitors.