AOpen AX5T

by Anand Lal Shimpi on August 13, 1997 7:13 PM EST
When the AMD K6 was released there were few motherboards which boasted K6 compatibility as well as reliability at higher bus speeds, out of the contestants only a few came out on top...the AOpen AX5T (the AP5T's ATX brother) was among those. However how well does it stand up to the competition now?

Motherboard Specifications

Socket Style: Socket 7
Chipset: i82430TX
Cache: 512KB
Form Factor: ATX
BUS Speeds: 50 / 60 / 66 / 75 / 83 MHz
Clock Multipliers: 1.5x / 2.0x / 2.5x / 3.0x / 3.5x
Voltages Supported: 2.8v / 2.9v / 3.2v / 3.45v / 3.52v
RAM Slots: 4 72pin SIMM Slots (EDO/FPM)
2 168pin DIMM Slots (SDRAM/EDO/FPM)
PCI/ISA Slots: 4 PCI Slots
4 ISA Slots (1 Shared / 4 Full Length)
PCI EIDE Controller: Super I/O
2 EIDE Channels
1 FDD Channel
2 Serial /1 EPP


The Good

The AOpen AX5T, although not really different than most other boards, places itself above the competition by excelling in a few areas. Manufacturing quality, and stability when using the 75 and 83.3MHz bus speeds. As usual, the AX5T comes equipped with 4 PCI, 4 ISA, 4 SIMM, and 2 DIMM slots. What really amazed me was the huge 1" heatsink found on the switching voltage regulator. That was the first thing that struck me about the AX5T...I opened up the box and out popped this huge reminded me of the first time I opened the box my Pentium II Heatsink came in. Another thing that surprised me about the AX5T, was its software bundle...yes, the AX5T has a software bundle! Its not much of a software bundle, but I like the idea of AOpen including a free copy of Norton Anti-Virus with their motherboard. I could only hope that other manufacturers will follow AOpen's example in this case. AOpen also took care of ensuring that our experience with the AX5T would be a reliable one by using high quality tatulum capacitors as well as providing us with CPU thermal protection (AX5T-3 only) which electronically slows down your CPU when the processor temperature peaks above 55 degrees Celsius. Again, AOpen has showed the customer that they care about the reliability of their motherboards. Performance and stability wise, the AX5T is much like all other TX based motherboards, quite fast and stable at high bus speeds when used with high quality SDRAM that is. Overall, the AX5T is a great product, and it still holds its ground as one of the best TX based motherboards since its release a few months back...

The Bad

The AOpen AX5T is a very stable motherboard, even when using the 83.3MHz bus speed, however this is the first motherboard I've tested, where clocking the Pentium MMX 200 at 250 caused severe hard disk errors and corruption. I've managed to take the Pentium MMX (and even the AMD K6 in some cases) up to 250MHz on a few HX and TX based motherboards (the most successful two being the ABIT IT5H and Megatrends HX83) and I've never experienced the "hard drive thrashing" that the AX5T threw at me. I guess its not that big of a loss...I just wouldn't recommend using the 250MHz setting with any 200MHz processor on this motherboard. Other than that, the AOpen AX5T is a great motherboard...a few more options under the Chipset Configuration of the AWARD BIOS Setup would've been nice...ah can never have it all =)


IRQ Usage

  • Allows user to Enable/Disable usage of IRQ12 for a PS/2 Mouse

  • Allows user to individually set IRQs for each Legacy ISA card

  • Allows user to reserve IRQ/DMA Channels if necessary

  • Auto-detects PnP Cards after HDD Detection


BIOS Settings

Here are my Recommended BIOS Settings for those of you who have been having problems with the AX5T and higher bus speeds (not sure why you would need to, the AX5T didn't give me any problems at higher bus speeds with aggressive memory timings). Below are my recommended settings for bus speeds < 66MHz, and 75/83.3MHz. If you are using Non-EDO RAM, then use the settings the in the 2nd (Non - EDO) column, if you are using SDRAM/EDO RAM with a 50/60/66MHz bus speed use the 3rd (66MHz Setting) column. The next column should be used if you are using the 75/83MHz bus speed. ! Finally, if you are looking for the safest and most stable setting, use the last column.

AOpen AX5T Chipset Features Setup

Item Non - EDO 66MHz Setting 75MHz Setting Safe Setting
Auto Configuration: Disabled Disabled Disabled Disabled
DRAM Leadoff Timing: 10/6/3/3 10/6/3/3 10/6/3/3 10/6/3/3
DRAM Read Burst (EDO/FP): x333/x444 x222/x333 x222/x333 x222/x333
DRAM Write Burst Timing: x333 x222 x222 x333
Fast EDO Lead Off: Disabled Enabled Enabled Disabled
Refresh RAS# Assertion: 4 Clks 4 Clks 4 Clks 4 Clks
DRAM Page Idle Timer: 4 2 4 8
DRAM Enhanced Paging: Enabled Enabled Enabled Enabled
SDRAM (CAS Lat/RAS-to-CAS): 3/3 2/2 3/3 3/3
SDRAM Speculative Read: Disabled Enabled Disabled Disabled
System BIOS Cacheable: Enabled Enabled Enabled Enabled
Video BIOS Cacheable: Enabled Enabled Enabled Enabled
8 Bit I/O Recovery Time: 1 1 1 2
16 Bit I/O Recovery Time: 1 1 1 2
Memory Hole At 15M - 16M: Disabled Disabled Disabled Disabled
PCI Passive Release: Enabled Enabled Enabled Enabled
PCI Delayed Transaction: Disabled Disabled Disabled Disabled
Mem. Drive Sr.(MA/RAS): 16mA/16mA 10mA/16mA 16mA/16mA 16mA/16mA


Recommended SDRAM

This little addition to my review layout was put in here just so you all can have an idea of what brand of SDRAM I recommend and have tested with the board, just to avoid problems in the future if you decide to purchase the board.

Recommended SDRAM: Advanced Megatrends SDRAM
SDRAM Tested: 2 x 32MB Advanced Megatrends SDRAM DIMMs

Manufacturer: Advanced Megatrends
Purchase Web-Site:

The Test
Comments Locked


View All Comments

Log in

Don't have an account? Sign up now