AOpen has received more AnandTech Editor's Choice Awards than any other manufacturer in the past few years. There is no doubt that AOpen's products are made with high quality and stability in mind. It seems that AOpen always listens to user's comments when producing a new board, as often suggestions seem to be implemented in sequent products.

Being one of the most profitable motherboard manufacturers, AOpen does not stop there. They always try to improve themselves by releasing different varieties of a product. In our Motherboards in 2001 Preview: Part 1 review we learned that AOpen is ready to switch gears to a new line of products based on new chipsets, namely the Intel i850, AMD 760, and VIA Apollo Pro 266.

But before the new products come along, AOpen has decided to make one final move in the VIA KT133 arena by releasing yet another new KT133 based product, the AK73 Pro. Since AOpen products have a long history of high quality and great performance, we eagerly waited for the board to arrive at the lab, even though the AK73 Pro comes comparatively late. So what did AOpen do to assure that the AK73 Pro is still a good contender? Let's find out.

The Good

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The AK73 Pro measures 12 by 9 inches, which is the average among most KT133 motherboards. The layout for the board is very clean, and AOpen did a very good job with the placement of different components. One problem arose when we noticed that a few capacitors are close to the CPU socket, so some users may have a problem installing some large heatsink and fan units, but users with moderately sized heatsinks should have no problem. The placement of the power supply connector is very appropriate, as the power supply cables do not block the CPU or the heatsink and fan unit. Moreover, the IDE connectors as well as the floppy connector are located right in front of the DIMM slots, so they will not affect the placement of any add-on cards.

As we have mentioned many times, even though implementation of the multiplier ratio settings is not part of the VIA KT133 chipset specifications, many users have considered this feature a standard for recent KT133 motherboards. One of the reasons is because overclocking AMD CPUs by changing the multipliers is far better than by changing the FSB speeds, since the KT133 chipset is currently unable to run the FSB at above 115MHz while maintaining stability in the vast majority of cases. On the other hand, it is not hard for users to unlock their processors for overclocking, and most AMD processors can sustain quite some overclocking. For more details, make sure you read our AMD Socket-A 133MHz FSB/DDR Overclocking Guide.

As a good listener to users' needs, the AK73 Pro includes the ability to modify the multiplier ratios. Changing the multiplier ratio is done through a set of 4 dipswitches where users can choose from sixteen settings between 5 and 12.5. The AK73 Pro also provides a set of FSB speed settings for users to modify from within the BIOS. The available values are 100 / 102 / 104 / 106 / 107 / 108 / 109 / 110 / 111 / 112 / 113 / 114 / 115 / 116 / 118 / 120 MHz. This should be enough for most users, but the lack of certain FSB speeds may hurt some user's potential for overclocking. Note that on the motherboard there is a jumper, which allows you to choose FSB speeds between 100MHz and 120MHz or between 124MHz to 166MHz. However, if you set the jumper for the 124MHz to 166MHz range, the system will not boot. AOpen has confirmed with us that this setting does not work on the AK73 Pro, and only the 100MHz 120MHz range is accessible. For KT133 motherboards, this is not a problem at all, but it does mean that AOpen will most likely stay with the same board design when they release the version of the board based on the VIA KT133A chipset. At that time, AOpen can simply enable the 124MHz to 166MHz range settings, and the motherboard will be able to support all AMD processors running 266 FSB.

To make this board even more complete for hardware enthusiasts, AOpen also allows users to tweak with the CPU core voltages as well as the I/O voltages. For the core voltage, users can choose from 1.100V to 1.850V in 0.025V increments, which should be more than enough to push the processors to the limit. The I/O voltage can range from 3.2V to 3.5V in 0.1V increments. Although we have yet to see evidence on whether the I/O voltage plays a role in overclocking, it is always nice to have them included, and will probably help to ensure stability of the system.

More Good

As usual, it is helpful to see how much overclocking we can do with this motherboard. We used an AMD Athlon (Thunderbird) 800MHz OEM processor, one 128MB Mushkin PC133 CAS2 SDRAM, and an NVidia Geforce2 GTS 32MB video card. The core voltage and the I/O voltage were stayed at default for fair comparison. We started out by changing the multiplier ratio, and we found that once again the 9.5 setting is the highest we could get before the system became unstable. When we tried to increase the FSB speeds, we found that 104MHz was the highest we could get. At the next setting, which is 106MHz, the system lost its stability. Here we can see the importance of having 1MHz increments between 100MHz and 115MHz. Therefore, the final clock speed we could achieve was 988MHz (105MHz x 9.5).

Just like most other KT133 motherboards, under the PC Health panel inside the BIOS users can look at two temperatures, one for the CPU and one for the system. There are a total of three fan connectors on the AK73 Pro, but it is only possible to read the speed of two of them.

The stability of AOpen boards has helped to gain a great amount of respect for the manufacturer; there was no way they are going to let go of that. In order to maintain the high level of stability that we have come to respect form AOpen, the AK73 Pro utilizes a few well known techniques. First off, AOpen does not focus on using very large size low ESR (Equivalent Series Resistance) capacitors. Instead, they use a greater number of smaller valued low ESR capacitors for a better distribution. The AK73 Pro has a total of thirteen 1500uF capacitors and two 330uF capacitors around the CPU socket and the VIA 8363 North Bridge. Moreover, you can also find six more 1500uF capacitors below the DIMM slots. These low ESR capacitors are very important for high-speed operation, to make sure that there is enough power for the CPU and to ensure the signals are clean enough.

In addition, one will also notice a total of eight voltage regulators on the AK73 Pro; regulators installed to ensure that the power circuit is supplying a steady voltage. Another factor towards stability is the use of surface mounts, something similar to capacitors but are much smaller and found all over the motherboard. Unfortunately, we are not able to learn too much about these devices.

Last of all, and probably the most important part, is the overall layout. One of the things that AOpen considered in the design of the AK73 Pro was the "Frequency Isolation Wall." It basically means that AOpen has tried to separate the motherboard into regions, where each region is running at similar frequency locally. This can minimize a lot of the signal interference that is normally encountered. In addition, AOpen took the time on routing and attempted to make sure that most traces operating at the same clock speed are almost the same length, meaning that the clock signals will arrive at different components at almost the same time.

With all the above effort AOpen put on the AK73 Pro, they once again produced a motherboard that's rock solid. The board crashed a total of 3 times in a 24-hour span during our stability tests, a very respectable amount, and ranked fourth in our KT133 motherboards roundup.

The Features

The VIA 8363 North Bridge sits to the left of the CPU socket, covered by the typical AOpen gold platted heat sink. It is the core of the KT133 chipset that provides all the major features of the KT133, including the 100 / 133MHz memory bus as well as AGP 4X support. The AGP Slot is a "universal slot," which means it is not keyed specifically for AGP 2X or AGP 4X cards, so you can install almost any current AGP card in the slot. At the end of the AGP slot, AOpen also makes use of a locking mechanism, similar to the one by used by EPoX, that helps hold the AGP card in place. It is a little clip that works similar to that of a DIMM slot clip by clipping into a small tab at the end of the AGP card.

The three DIMM slots on the AK73 Pro support up to a maximum of 1.5GB SDRAM. One main feature of the VIA 8363 North Bridge is that the memory controller allows users to run their memory at either 100MHz or 133MHz. Therefore, users with PC133 SDRAM can take advantage of the increased bandwidth over PC100 SDRAM by going from 800MB/s to 1.06GB/s. This can be done easily in the BIOS by choosing either a 100MHz or a 133MHz memory clock. There is also a setting for CAS latency in the BIOS, so you can push your memory to the limit.

The AK73 Pro also uses the VIA 686B as the South Bridge. The 686B is pin compatible with the 686A, and they have similar features as well. They both have a second USB controller hub and an integrated PCI to ISA bridge. The advantage of the 686B over 686A is that it supports Ultra ATA 100, whereas the 686A only supports Ultra ATA 66. At this point, there is no hard drive out there with a sustained transfer rate of higher than 40MB/sec, so Ultra ATA 100 port is not really necessary. However, with the current pace of technology, we don't think it will be long before that barrier is broken, making it a definite plus for the motherboard to include Ultra ATA 100 support. The Ultra ATA 100 controller provides two IDE channels that support up to 4 IDE devices (two per channel).

Two traditional USB ports are mounted at the back of the motherboard together with the serial / parallel ports, and there are connectors ready for a third and fourth USB port the front of the board. In order to help users take advantage of the extra USB connectors, AOpen includes a set of two USB headers, so that users can setup their third and fourth USB ports easily.

The 5/1/1/0 (PCI/AGP/AMR/ISA) expansion slot configuration on the AK73 Pro should be enough for most users, though it is definitely not the most flexible one. For starters, the AMR slot is probably useless for most AnandTech readers. The 5 PCI slots should be enough, but we have seen motherboards with 6 PCI slots by using a PCI arbiter chip, which gives users more flexibility. Moreover, the lack of an ISA slot also marks eliminates this motherboard from the list of users who still want to retain their old ISA devices.

The AK73 Pro uses the AD 1885 AC 97 CODEC to provide basic on-board sound. This AC'97 audio provides some basic sound functionality for users on a budget, but for those who are serious about sound should definitely go for a true hardware-based PCI solution.

The AK73 Pro also comes with the famous AOpen Die Hard BIOS setup. Basically AOpen puts two BIOS chips on the board. For most of the time, only one of the two BIOS chips is active. If the BIOS chip is corrupted during a BIOS update or a virus attack, the second BIOS will start functioning and allow users to boot up the machine using the second backup BIOS.

AOpen also includes the Dr. Voice and the Dr. LED as optional accessories. Dr. Voice is a diagnostic tool for users to troubleshoot their systems when errors occur during boot up. Dr. LED is also for diagnostic purposes; it is a set of eight LED's, which also try to tell the users which part of the motherboard might be having problems.

For installation, AOpen figured out a way to accommodate users from varying backgrounds. Inside the AK73 Pro, you can find a poster, which contains steps for easy installation and setup of the motherboard. On the other hand, the manual contains all the exact details on the motherboard. The manual is simply excellent. It contains all the information on jumpers, connectors, as well as dipswitches. It also talks about the installation of the board, CPU, and memory. Detailed explanation of each BIOS setting makes this manual a very good read, as it also contains a lot of technical explanation on the design of the motherboard.

There are two CDs bundled with the motherboard. One contains all the drivers and utilities you will need for setting up the motherboard and sound devices. The second CD is the Norton Antivirus 6.0. Some other manufacturers include older versions of this software, but AOpen makes sure they are including a more recent version.

The Bad

It would be even better if AOpen included the multiplier ratio settings inside the BIOS instead of using the dipswitches.

The expansion slot configuration is not bad, but lacks the flexibility for some users.

USB Compatibility

• Number of Front Universal Serial Bus Root Ports: 2
• Number of Rear Universal Serial Bus Root Ports: 2
• USB IRQ Enable/Disable in BIOS: Yes
• USB Keyboard Support in BIOS: Yes

Recommended SDRAM

Recommended SDRAM: 1 x 128MB Corsair PC133 SDRAM; 1 x 128MB Mushkin PC133 SDRAM

SDRAM Tested: 1 x 128MB Mushkin PC133 SDRAM

Manufacturer: Corsair
Purchase Website: http://www.corsairmicro.com

Manufacturer: Mushkin
Purchase Website: http://www.mushkin.com

The Test

In recent times, choosing a motherboard cannot be completely determined by a Winstone score. Now, many boards come within one Winstone point of each other and therefore the need to benchmark boards against each other falls. Therefore you should not base your decision entirely on the benchmarks you see here, but also on the technical features and advantages of this particular board, seeing as that will probably make the greatest difference in your overall experience.

Click Here to learn about AnandTech's Motherboard Testing Methodology.

How it Rates