by Anand Lal Shimpi on June 9, 1997 7:08 PM EST
A few months back, I went out and bought an ABIT AX5 just after its release. Unfortunately, the board I came home with was plagued with problems ranging from the SoftMenu CPU Setup to the CMOS battery. Naturally, based on this, I had no option other than to give the board a bad review. However, since then, ABIT has released a newer revision of the AX5, revision 2.2 which supposedly fixed the very problems I, as well as other AX5 owners experienced. At first I was very skeptical, however ABIT contacted me asking for a re-evaluation of their AX5. So, in order to be fair to ABIT, as well as all of you, I re-reviewed the ABIT AX5 and the results I came across have produced some interesting conclusions. Has ABIT fixed the problems with the original AX5 in the newer revision? Let's find out...

Motherboard Specifications

Socket Style: Socket 7
Chipset: i82430TX
Cache: 512KB
Form Factor: ATX
BUS Speeds: 50 / 55 / 60 / 66 / 68 / 75 / 83 MHz
Clock Multipliers: 2.0x / 2.5x / 3.0x / 3.5x / 4.5x / 5.0x / 5.5x
Voltages Supported: 2.5 / 2.7 / 2.8 / 2.9 / 3.2 / 3.38 3.5
RAM Slots: 4 72pin SIMM Slots (EDO/FPM)
3 168pin DIMM Slots (EDO/FPM)
PCI/ISA Slots: 4 PCI Slots
4 ISA Slots (1 Shared / 4 Full Length)
BIOS: AWARD PnP BIOS w/ SoftMenu CPU Setup
PCI EIDE Controller: Super I/O
2 EIDE Channels
1 FDD Channel
2 Serial /1 EPP


The Good

I should say this before commenting on any aspects of the AX5. In revision 2.2 and later of the ABIT AX5 motherboard all of the problems I had originally experienced were not present and apparently have been corrected. ABIT also made some significant improvements with this revision of the AX5, which easily make it one of the best TX based motherboards I have even tested. The AX5 features the trademark 3 voltage regulators for added stability, as well as the 3 DIMM slots to allow the user to break that 64MB RAM barrier although the chipset still only caches the first 64MB of RAM. Along with that, the AX5 features 4 SIMM slots, 4 PCI and 4 ISA slots. Like many other TX based boards, the AX5 does come in an ATX form factor and abides by the specifications strictly. It is the ATX form factor which allows it to feature the great expansion capabilities it has. For those of you that are ATX challenged, ABIT has also made a scaled down version of the AX5 in an AT form factor, named accordingly, the PX5 (see ABIT PX5 Review - Coming Soon). If you aren't familiar with the Jumperless style of ABIT motherboards, featuring the patented SoftMenu CPU setup, here is a quick run-through. You basically install all of your components in your system, without worrying about any jumpers etc..., fire it up, enter the BIOS setup utility, and then setup your CPU in the BIOS. Sounds easy, huh? Well it is, and unlike previous versions of the AX5, r2.2 of this board retains all data stored in the SoftMenu setup upon a reboot.

The AX5 Revision 2.2 in my opinion, is comparable to the Shuttle HOT-569 in many aspects. It fully supports the 50, 60, 66, 68 (turbo frequency), 75, and 83MHz bus speeds as well as a CPU core voltage as low as 2.5v which should be close to the required voltage of the upcoming AMD K6/266. The familiar AWARD BIOS Setup Utility of the AX5 is also a major plus, however, lets get to the performance of this bad-boy before jumping to any conclusions...

Performance-wise, the AX5 is one of the fastest TX boards as well as one of the fastest Socket-7 motherboards I have tested. With all processors the AX5 produced some excellent benchmark results, including the tests with the Cyrix 6x86MX, a processor known to perform better on non-Intel based chipsets. Did ABIT fix absolutely everything with the AX5 though...?

The Bad

I reported earlier that I was having huge problems with the ABIT AX5 (Revision 2.2) and SDRAM with the 83.3MHz bus speed setting. Luckily, this problem is only limited to revisions of the motherboard prior to 2.21. Apparently, all revisions after 2.2 (2.21 and 2.22) work perfectly with pairs of SDRAM and the 83.3MHz bus speeds. So the only complaint about the AX5 is that you should be sure not to get a revision other than the absolute latest which may cause a small amount of trouble for some. Be sure to request revision 2.21 or later by NAME when ordering from a reliable vendor, otherwise don't plan to use the 83MHz bus speed with pairs of SDRAM anytime soon...


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 IT5H and higher bus speeds. Below are my recommended settings for bus speeds < 66MHz, 75MHz, and 83.3MHz. If you are using Non-EDO RAM, then use the settings the in the 2nd (Non - EDO) column, if you are using EDO RAM with a 50/60/66MHz bus speed use the 3rd (66MHz Setting) column. If you are using EDO RAM with a 75/83.3MHz bus speed use the 4th (75/83MHz Setting) column. Finally, if you are looking for the safest and most stable setting, use the last column.

AX5 Chipset Features Setup

Item Non - EDO 66MHz Setting 75/83MHz Setting Safe Setting
Auto Configuration: Disabled Disabled Disabled Enabled
DRAM Leadoff Timing: 11/7/3 10/6/3 10/6/3 11/7/3
DRAM Read Burst (EDO/FPM): x222/x333 x222/x333 x222/x333 x444/x444
DRAM Write Burst Timing: x222 x222 x222 x333
Fast EDO Lead Off: Disabled Enabled Enabled Disabled
DRAM Write Burst Timing: x333 x222 x222 x222
Turbo Read Leadoff: Disabled Enabled Disabled Disabled
Refresh RAS# Assertion: 4 Clks 4 Clks 4 Clks 5 Clks
Fast RAS to CAS Delay: 3 2 3 3
DRAM Page Idle Timer: 2 Clks 2 Clks 2 Clks 4 Clks
DRAM Enhanced Paging: Enabled Enabled Enabled Enabled
Fast MA to RAS# Delay: 2 Clks 2 Clks 2 Clks 2 Clks
SDRAM(CAS Lat/RAS-to-CAS): 3/3 2/2 3/3 3/3
SDRAM Speculative Read: Disabled Enabled Disabled Disabled
System BIOS Cacheable: Disabled Disabled Disabled Disabled
Video BIOS Cacheable: Enabled Enabled Enabled Enabled
8 Bit I/O Recovery Time: 2 2 2 3
16 Bit I/O Recovery Time: 3 3 3 4
Memory Hole At 15M-16M: Disabled Disabled Disabled Disabled
PCI 2.1 Compliance: Enabled Enabled Enabled Disabled



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; Corsair SDRAM; SmarTech SDRAM
SDRAM Tested: 2 x 32MB Advanced Megatrends SDRAM DIMMs; 2 x 32MB SmarTech SDRAM DIMMs; 2 x 32MB Corsair SDRAM DIMMs

SDRAM to Avoid with this board: Any combination of 2 SDRAM DIMMs if you are using revision 2.2 or earlier, not a problem with all later revisions.

Manufacturer: Advanced Megatrends
Purchase Web-Site: http://www.megacom.com

Manufacturer: Corsair Microsystems
Purchase Web-Site: http://www.nf-ny.com/nfny/comp.html


The Test
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