This page is intended to answer some of the more common questions about the VX-Pro+ motherboard manufactured by PCChips, if there's something you think should be in here and it's not please use the email link below and I'll update the page!

Thanks to Peter Missel for his help ensuring this information is as accurate as we think we can make it!


My motherboard looks the same, but it's an Amptron/Ability/Matsonic etc?

The PCChips M537DMA motherboard has been sold under a number of different names including Amptron, Ability, Houston, and Matsonic. They are all the same board and can be identified by the BIOS identification string during bootup, which shoud be :- 04/30/98-M537+UMC8670F-2A5LDH09C-00. Note that the date string and next series of characters might be different depending upon the BIOS release you are running, the set of digits 2A5LDH0 should be the same.


 Who makes the VX-Pro+ chipset?

The VX-Pro+ chipset is made by VIA Technologies and is known to them as the Apollo VPX/97.


What is the difference between the VX-Pro+ and the Intel VX chipsets?

The VIA website lists the differences between the chipsets, but in summary, the VX-Pro+ chipset is a sort of mixture between the Intel VX and Intel TX chipsets. One significant advantage over the Intel VX is that it supports UDMA hard disk drives for increased performance.


What processors work with this board?

Officially the M537DMA will support processors from Intel, Cyrix and AMD upto and including 233Mhz. The board supports MMX technology CPUs too.

Unofficially, is is possible to get 262Mhz by using the 75Mhz Front Side Bus (FSB) setting, and if you are able to use the 83Mhz FSB successfully you can get 290Mhz.

If you are more adventurous you can modify the board as detailed elsewhere in the site and get access to more multiplier settings to allow 350,400,450 etc Mhz operation.

I have personally managed to get an AMD K6/266 to run at 337Mhz and a K6-2/350 to run at 412Mhz.

Now reports are coming in of K6-2 400 and 450 processors operating at upto 500Mhz (if you are lucky enough to get 83Mhz FSB working) and also a K6-3/400.

I'll post comparative benchmarks soon.


My K6-2 CPU doesn't seem to be optimised?

If your K6-2 is one of those built on the 'CXT' core then the BIOS (even the 04/30/98 version) will not set the registers correctly for write enable or write combining. You will have to use an alternative utility to set the registers when you boot the system. I have found the program "SETK6" by Andreas Stiller to work very well.


Can I run my AMD K6 at 2.5V?

I have, and you might be able to do so as well BUT REMEMBER, the 'normal' range for the K6 and K6-2 is 2.1V to 2.4V, and AMD state that the absolute maximum 2.5V - long term useage of 2.5V may result in CPU failures. Also, running high speed (350+Mhz) at 2.5V will increase the loads on the motherboard regulator circuitry which may in time fail.

If you really want to use 2.5V then I would recommend that you have a (very) high efficiency heatsink and fan combination and additional case ventilation/fans due to the heat generated.


I've installed a 64Mb SDRAM module but it only registers 16Mb?

The VIA chipset was supposed to be compatible with 64Mbit technology, your manual probably states this too (mine does) however it has limitations. It would appear that it is possible to use 64Mbit technology SDRAM modules so long as their organisation is 8*8 (look for 8 RAM chips on the DIMM) rather than the more common 4*16.

For 128Mbyte DIMMS you would need to look for double sided DIMMS with 16 individual RAM chips on.

You may need to also update your BIOS to the 04/30/98 version to get this to work even if you have 8*8 modules.

See the DIMM survey and results for more information.


Can I run EDO SIMMs and SDRAM DIMMs together?

It says so in the manual, but I've not tried it myself - DIMM2 cannot be used in this mode. I know other people who do run a mix, and I have seen it reported that the SDRAM speed will be lowered to that of the EDO. Ideally you should run only SDRAM as this provides the highest performance on the board.

Further information seems to indicate that, as SDRAM requires 3.3V (generally) and EDO has 5V, the two types may be incompatible. It used to be possible to get EDO DIMMS which (presumably) would be 5V and have no problem.

The 'best bet' would be to buy 64Mbit SDRAMs when the prices are low and ditch the EDO SIMMs.


What is the latest BIOS, will there be updates?

The latest BIOS is dated 04/30/98 and is available from the various manufacturers web sites (PPChips, Amptron etc). Due to the age of the board it is highly unlikely that any further updates will be provided.

For further BIOS information on this and other boards, try 'WIMs BIOS page' at www.ping.be


Can I run an AMD K6-3?

It now looks as though it IS possible to run a K6-3 on this board, I have email confirmation of successful installation of a K6-3/400 running at 6x66 2.5V. As the 6x multiplier is a remapped 2x and 2.5 is a standard voltage option, no modifications were even required to the motherboard.

This news may be unfortunately short lived, as the K6-3 is now a discontinued part according to AMD. So we will have to wait for the now delayed (as of March 2000) K6-2+ to get any more AMD processors with on-die L2 cache.


My CMOS configuration is lost when I power down?

This could be the sign of a dying motherboard, but try cleaning the contacts and the battery surfaces very carefully using an alcohol based cleaner and gently bend the contact to make a really good connection. Oh and don't forget to try replacing the battery itself!!


My CD-ROM isn't detected during the BOOT sequence?

There are reports that newer CD-ROMs, CDRs and ZIP drives are not autodetected by the BIOS during BOOT. I don't have the problem with my HP Surestore 8100 or with my older Sony 16 speed or Mitsumi 24 speed CDROMs.

All Hard disks seem to be identified correctly.

Windows OS seems to identify the hardware (NOT ZIP) once booted too and operate correctly, so this is a strange one! If anyone has any ideas, or further confirmation of the types of devices I would welcome them.


  How do I set the clock to 83Mhz?

The VX-Pro+ should be capable of running the FSB at 83Mhz, and the jumper settings are screen printed onto the motherboard itself - but they're not in the manual!

So, the settings are; JP3 A=up, B=up, C=down (where up jumpers pins 1&2).

I would also recommend that you set JP3 D=down to lock the PCI bus frequency to the standard 33Mhz as problems may be experienced with some peripherals if JP3 D is 'up' which clocks the PCI bus at 1/2 the FSB (83/41.5Mhz).


What is the fastest processor reported working?

Well, I've only managed 412.5Mhz with a K6-2/350, but I know that the AMD K6-2/400 has been run at 450Mhz by using an FSB of 75Mhz and a multiplier setting of 2x (which is remapped to 6x by the processor).

By using SDRAM memory only in the system the speed was increased to 6x83 -

A massive 498Mhz - close enough to be called a '500'?

There are indications that AMD may continue to 'reuse' the multiplier settings i.e. to give us 6.5x and 7x so we could be in for even more performance from our boards!

I have also had confirmation of a K6-3/400 working without any hardware modifications to the motherboard. This is because the Multiplier is set to '2' which internally maps to 6x in the processor and the default voltage for this chip is 2.4V - so running at 2.5 is reasonable. I'll post benchmark results soon.