As the time grows near for 1GHz Athlons to become more commonplace as well as in anticipation of the release of the Thunderbird core (Athlon + 256KB on-die L2 cache), motherboard manufacturers are doing whatever is in their power to release their KX133 motherboards on-time and without any of the problems that may have plagued their VIA based solutions in the past.

The Athlon motherboard market essentially belongs to those motherboard manufacturers that are bold enough to pursue Athlon motherboard designs. Since the market isn't nearly as saturated as the Intel 440BX motherboard market for example, it is quite attractive to some of the larger motherboard manufacturers that wish to gain as much ground as possible in virtually all areas.

OEMs are obviously taking the Athlon seriously, and scoring OEM deals is what truly separates the successful motherboard manufacturers from those that aren't so successful. With a growing demand for Athlon systems, OEMs are definitely on the lookout for Athlon motherboards from the manufacturers that supply them boards for the rest of their, non-Athlon, product line. If those manufacturers don't have Athlon products, then it may be time for that particular OEM to begin soliciting help from some of the manufacturer's competitors. One of the world's most profitable motherboard manufacturers, AOpen, wasn't about to let this market fall into the hands of their competitors.

Long time AnandTech readers will know that there hasn't been a manufacturer that has received more of our Editor's Choice Awards than AOpen in the past couple of years. AOpen has consistently been able to deliver the features users demand from a motherboard while maintaining a respectable level of stability through their excellent choice in components as well as their extremely rigorous QA testing procedures that take place before you even set your hands on one of their motherboards.

Because of AOpen's virtually spotless history, when they announced that they would be producing an Athlon motherboard this year we were definitely looking forward to getting our hands on what would surely turn out to be one of the best Athlon motherboards to hit the streets. We were originally told to wait until the end of January 2000 for AOpen's AK72, their KX133 based Athlon motherboard, unfortunately after a few more delays that plagued not only AOpen's project but KX133 motherboards from virtually every motherboard manufacturer other than EPoX, the AK72 didn't make its way out of AOpen's plants in January as planned.

After a bit of tweaking of the design, the AK72 is finally ready for the public to see and the reviewers to judge. While the AK72 didn't step away with an Editor's Choice award like most of AOpen's previous submissions to AnandTech for evaluation, let's take a look at how well it stacks up to the rest of the Athlon motherboard market out there and see if it measures up to our high expectations from AOpen.

The Good

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The first thing you notice about the AK72 is its incredible size. The board is built upon a PCB that is much larger than most regular ATX designs and more closely resembles an extended ATX design that is usually reserved for dual processor motherboards. The board itself is about the size of FIC's SD-11 which is the only other oversized Athlon motherboard that we've seen in the lab. The reasons for AOpen choosing such a large PCB design for the AK72 aren't very clear because it is more expensive to produce a board with a larger surface area than it is to produce one with a smaller surface area simply because you save on PCB costs with a smaller layout. Also, with a larger motherboard layout you can run into space constraints in smaller ATX cases that could possibly hinder the cooling efficiency of your setup because of cable clutter, or the motherboard may not even be able to fit properly if you have a small enough ATX case. This is something you'll definitely want to take into account with the AK72 since it is about a full inch (2.54cm) deeper than most ATX motherboards.

The AK72, like most Athlon boards being released these days, is based on VIA's KX133 chipset. The KX133 makes use of the VIA 371 North Bridge that is covered by the very familiar green AOpen heatsink and located between the Slot-A interface connector and the three DIMM slots. The 371 North Bridge provides for the board's AGP 4X support in addition to support for four different memory types: PC100, PC133, VC100, and VC133 SDRAM.

The main benefit of the 371 North Bridge is its support for PC133 SDRAM which, when running at 133MHz, can offer up to a 20% improvement in performance because of the 33% increase in peak memory bandwidth. While the 371's integrated memory controller supports Virtual Channel (VC) SDRAM in both 100 and 133MHz versions, the relative lack of any Virtual Channel SDRAM in the market as well as the negligible real world performance improvements offered by VC-SDRAM over regular PC100/PC133 SDRAM make this feature something that looks good on paper but doesn't really come in handy in the real world. This is unlikely to change as VC-SDRAM will most likely be overshadowed DDR SDRAM which is due to ramp up in quantities later this year.

Regardless, the AK72, like all other KX133 boards, features three DIMM slots all capable of accepting any of the four aforementioned memory types. In the event that your memory can't run at 133MHz, the chipset allows for a 3:3 ratio to be used with the FSB frequency to let your memory bus operate at 100MHz (along with your FSB at 100MHz) while still offering PC133 memory owners the option of using a 4:3 ratio thus placing the memory bus at 133MHz while the FSB still runs at 100MHz.

VIA recommends that their 686A Super South Bridge be used in combination with the 371 North Bridge on all KX133 designs, so AOpen decided to abide by the design guide and outfitted the AK72 with the 686A Super South Bridge. The benefits of doing this seem kind of silly when you consider the fact that the AK72 features such a large PCB. The 686A helps to reduce the overall cost of the motherboard by integrating hardware monitoring functionality, an ISA bridge, as well as the basic I/O controller functions into a single South Bridge chip.

The overall cost of the motherboard is reduced because the manufacturer doesn't have to use external chips for all of these functions that not only add to the cost of the board but also occupy PCB space on the board which causes the board to be larger and thus cost more. But in the case of the AK72, AOpen had more than enough room on the board for space constraints not to be a major issue. In this case the 686A is still a more cost effective alternative to the 596B South Bridge that doesn't boast the same high levels of integration, but AOpen's design negates some of the benefits of using this particular chip.

The 686A also provides support for a total of 4 USB ports, unfortunately AOpen failed to provide an external USB header for the remaining two ports supported by the chip.

Things get even more odd when you look at the AK72's expansion slot layout. The board itself features a 5/1/1/1 (PCI/AGP/ISA/AMR) expansion slot configuration, but the slots themselves are laid out in a manner that once again, doesn't make optimal use of the space on the board. Instead of sharing the AMR slot with a PCI slot so that it would not occupy the space required for another slot on the motherboard, AOpen chose to stick the AMR slot at the end of the board where it occupies the space that could have been used to provide for a sixth PCI slot. The AK72 covers all ends in terms of expansion, and all of the slots are capable of accepting full length cards which is one of the very few benefits of the AK72's larger PCB design.

The AMR slot on the board is driven by Analog Devices' AD1881 codec which is a very popular chip among motherboard manufacturers. The sound quality is ok, but you can't really expect all that much more from a software driven audio codec. Most users will want to go with their own hardware PCI sound solutions.

In accordance with the usual AOpen style, the Slot-A interface is surrounded by six hefty heatsinks that are mounted on the switching voltage regulators by the connector as well as 14 2200uF capacitors. These 14 capacitors are the same low ESR (equivalent series resistance) capacitors from the AX6BC Pro Gold and AX6BC Pro Gold II Millennium Edition that supposedly allow for increased stability. Whether these low ESR capacitors actually improve stability is up to you to decide, AOpen was just as stable before they started using low ESR caps as they are now with the new caps.

The AK72 features AOpen's jumperless CPU setup utility that is located within the AWARD 6.00PG BIOS setup on the board. While the utility obviously doesn't allow for the manual adjustment of the Athlon's clock multiplier (that is left up to external overclocking devices) it does allow for the manual adjustment of the processor's core voltage in 0.05v increments and lets you choose the 110 and 115MHz overclocked FSB settings. From our tests in the past, we have yet to encounter an Athlon motherboard that could even so much as boot at a FSB frequency setting much greater than 110MHz. While there have been some success stories for the most part, 110MHz is about the maximum FSB frequency you can expect to attain on a current or previous generation Athlon motherboard.

It is very welcoming to see the return of AOpen's high quality written documentation in the form of the AK72's User's Guide which is a comprehensive manual that describes the features of the board as well as in the form of an Easy Installation Guide poster that guides you through the setup of your AK72 based system. For quite some time it seemed like AOpen had ditched the idea of bundling written documentation with their products, but it's good to see that they have elected to include some pretty good documentation with this board that could really come in handy because of the drivers that need to be installed for proper support of the KX133 chipset.

The Bad

In spite of carrying the AOpen name, the AK72 wasn't as stable as most AOpen boards we've encountered in the past. The board itself was fairly stable but definitely not as stable as the ASUS K7V-RM and definitely not up to par with AOpen's award winning BX boards in terms of stability. When you're in a position like AOpen there are definitely very high expectations, and when those expectations aren't met the disappointment can be great.

The layout and incredible size of the board is pretty unusual for AOpen as well, the board may have problems in cramped cases but luckily the positioning of the DIMM slots makes it so that you shouldn't have any problem occupying all three DIMM slots, even in the smallest of ATX cases.

It's a bit disappointing to see AOpen sacrifice a potential sixth PCI slot for an AMR slot which, if positioned as a shared slot could have easily made room for a sixth PCI slot. It would have also been nice for AOpen to include a set of USB connectors for use with the USB header near the PCI slots that controls USB 3&4, unfortunately it seems as if you can't always get everything you hope for.

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 Corsair PC133 SDRAM; 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 shouldn't 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.

While the AK72 is definitely better than your average Athlon motherboard, we honestly expected much more from AOpen, especially considering our past experiences with them. There is nothing wrong with the AK72, but the board isn't up to par with what we normally see from AOpen which is a bit saddening.

There is nothing wrong with the board in particular, granted it is a tad on the large side, but with the K7V-RM and the K7V just around the corner, there isn't much that is going for the AK72 right now other than the AOpen name.

It's a good board, but not the usual AOpen quality we're used to.

How it Rates