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mr_realtimeFlag for United States of America

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What Kind of DIMM for VX-Pro+ Motherboard?

I just bought a 64meg DIMM for my VX-Pro+ (Elpina) motherboard.  The label on the package reads "8x64-10ns SDRAM, unbuffered w/ EPROM."  

Problem:  When booted, the machine only sees 16meg out of 64.

Question:  Is this the right RAM for the DIMM slot on this motherboard?

I was intending on using it with the 48meg of EDO SIMMS currently installed, but I'm having this problem even with the SIMMS removed.

I didn't see any relevant settings in the bios setup or on the motherboard jumpers.  I have no manual for the motherboard.
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satwa

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swwelsh

I've had the same problem with using a new 64meg dimm in a vxpro board. I think the vxpro used memory with a different voltage setting, and I'm not sure it can deal with a dimm of more than 32meg. I would call around to local computer stores until you find someone who knows where to get dimms that will work with the vxpro. I can tell you that all motherboard manuals recommend against mixing dimms with simms
I have 3 VXPRO chipset boards in computers that I have built for customers,
they are not ELPINA, but are AMPTRON, and they all have no trouble using
8X64 10ns SDRAM modules like yours.  Your Elpina board was made by
PC Chips of Hong Kong for Abilty of Taiwan.  PC Chips make all ELPINA boards
for Ability.  I have tried to get to the PC Chips site to download a manual for
you, but so far today, the site will not respond, but as soon as they do, I'll
get you the manual for the ELPINA board.
As far as I know there is NO difference in the VXPRO+ chipset in your
board and the ones in the AMPTRON Boards, and all the VXPRO+
AMPTRON boards will run and recognize 8 x 64 SDRAM 10ns with EEPROM
which is designed for a 66 MHZ bus.
I have managed to download a copy of your motherboard manual, and it
plainly states that you can use the type DIMM that you describe in your
question.  If you would like a copy of this, please e-mail me at:

emc@impresso.com  and I'll send it to you as an e-mail attachment.

Your will need Adobe Acrobat reader to read it, as it is in .pdf format.
Avatar of mr_realtime

ASKER

I can't accept or reject satwa's answer yet.

I found the Amptron Vx-Pro manual and downloaded it (fell asleep before finding the Elpina one).  The board layout, jumpers, etc. look identical to mine.  The chipset looks like only a minor variation.

I confirmed that I DIMM voltage setting at 3.3v, so I would be inclined to take satwa's answer at face value, except...

I bought two DIMMS.  The 64meg one was for me, a 32meg PC-100 for a friend.  When only 16meg out of 64 was seen by my VX-Pro, I put in the 32meg DIMM and only 8meg was seen.  However, I have confirmed it to be a good DIMM, because his Dell sees all 32meg.

There must be another piece to the puzzle...
PC CHIPS also make this motherboard for a company called Matsonic and in
the Matsonic VXPRO+ motherboard manual there is this notation:

"The SDRAM must be buffered"

I assume by the specs. that you listed your 64 MB DIMM is unbuffered.

If so return it to the vendor for a buffered DIMM and try that one.
> You have bad RAM.

Incorrect.  

You have an Intel 430 motherboard, correct?
So do I, and I saw the same symptoms.

This motherboard requires special DIMMs.

The usual symptom of putting "new" DIMMs into this "old"
motherboard is that the BIOS only detects 25% of the
capacity of the DIMM, i.e., it finds 16MB on a 64MB DIMM.
So, 25% of 32MB is 8MB, and 25% of 64MB is 16MB.

SWWELSH was correct to say:
> I would call around to local computer stores
> until you find someone who knows where to
> get DIMMs that will work with the vxpro.

I searched, via http://WWW.DejaNews.COM,
and this is a quite-common complaint for owners of 430VX motherboards.
This chipset is not an Intel 430VX it is a VXPRO+ made by Via Appollo and if
you had bothered to read my last comment to Mr. Realtime you would see
where I informed him to exchange his present Ram for buffered ram and give it a
try.  The same board is made for Matsonic by PC CHIPS and in the Matsonic
manual for a Matsonic VXPRO+ with Via Appollo chipset, Matsonic tell their
customers to use buffered SDRAM DIMMS.
The RAM is, in fact, GOOD -- I just tested it in another machine of approximately the same vintage.  However, I took the RAM from that machine and put it in the VX-Pro+  and it worked.  The RAM doesn't say whether or not it is buffered, so I'm not sure whether the truth lies with satwa's "unbuffered" or otta's "old" DIMM idea.

But, since the RAM swap is an acceptable solution for me, I'm closing this question.
> I'm closing this question.

I'm glad to see that you "solved" your problem with "incompatible" (not truly "bad") RAM.