AOpen AK73 ProA KT133A ATX

The Basics

The VIA 8363A North Bridge sits between the CPU socket and the AGP slot. As the core of the KT133A chipset, it provides all the major features of the chipset, including the 100 / 133MHz FSB and memory bus, as well as AGP 1X/2X/4X support. The AGP slot on the AK73 ProA, like most other AGP 4X slots, is a universal slot, so you can use almost any kind of AGP video card currently available without problems.   Like the AK73 Pro, AOpen has included a clip at the end of the AGP slot to help lock the AGP card in place during shipping.

The clip helps to hold the AGP card in place.

With the new 8363A North Bridge, we have official support for 133MHz DDR FSB (266MHz effective) Athlons. With the old 1.2GHz Athlons, you were limited to a FSB speed of 100MHz and a multiplier of 12, meaning the CPU ran twelve times faster than the FSB.  Now, the KT133A chipset allows you to have a FSB speed of 133MHz, meaning that with the same 1.2GHz chip, you can lower the multiplier to 9 and boost the overall performance while remaining at the default clock speed. It should be noted that this is still considered overclocking, but our experience shows that most Athlon and Duron CPU’s are able to handle such a configuration without a hitch. However, in order to do that, you need a motherboard that’s capable of changing the multiplier of a Socket-A processor. You’ll also need to prepare your CPU for overclocking, a subject we’ve touched on in our Socket-A Athlon/Duron Overclocking Guide. We’ll talk about the overclocking abilities of the AK73 ProA specifically a bit later.

Similar to most other KT133A boards, the AK73 ProA has a total of three DIMM slots supporting up to 1.5GB SDRAM. The memory controller allows you to run your memory at either 100MHz or 133MHz, depending on your FSB choice. When running in the 100MHz FSB range, you have the option to run your memory at host clock (FSB speed) or host clock + PCI clock. However, at 133 MHz FSB and above, the chipset only allows synchronous memory operation. This is not a fault of the AK73 ProA, but rather a part of the KT133A specifications, which specifies FSB:memory ratios of 100:100, 100:133, or 133:133.

AOpen has been using the VIA 686B South Bridge since the AK73 Pro a while back.  The newer VIA 686B South Bridge supports Ultra ATA 100, whereas the older 686A, only supports Ultra ATA 66. The Ultra ATA 100 controller provides two IDE channels that support up to 4 IDE devices (two per channel).

However, unlike many other manufacturers, AOpen currently has no intention of integrating an on-board IDE RAID controller.  Such a controller could be used as either a second controller for more devices or to set up a RAID configuration  for better performance and/or reliability.

The 686B South Bridge also supports two USB root hubs. The first hub provides the two traditional USB ports found at the back of the motherboard with the serial / parallel ports. The second set of USB ports is located at the front edge of the board, next to the BIOS chips. As they have done with their previous KT133 solutions, AOpen includes the necessary USB bracket so you can take advantage of the third and fourth USB ports easily.

The 5/1/0/1 (PCI/AGP/ISA/AMR) expansion slot design is not particularly exciting, but is still enough for the majority of users.  We wish AOpen would have included six PCI slots, something most other manufacturers have done with recent products. Further, for most AnandTech readers, the choice of an AMR slot instead of an ISA slot is somewhat suspect since AMR is pretty much useless due to the lack of availability for these cards to the public.  For OEM builders this configuration should be enough, but for most AnandTech readers, this is quite disappointing. 

For on-board audio, AOpen continues to go with Analog Devices for host-based AC’97 audio, using the AD 1885 on the AK73 ProA.  Once again, this feature is more designed for OEM builders in order to provide cheap systems for users.  For anything beyond basic sound, we recommend going with a hardware-based PCI audio device for better sound quality and performance.

AC’97 CODEC.