VxPro motherboard and upgrading memory

[Jonathan Lonsdale]

I was recently given an old PC which I'm looking to upgrade and give
to my uncle.

The bios boot-up string is: VxPro-UMC8670-2A5LAH09C-00.

I tracked down a motherboard manual for the PM-8600 and while the
layout is not quite the same it's very similar.

Looking in that manual it suggests that the board can take up to 128
MB of EDO DRAM SIMMS and up to 256 MB of EDO DRAM/SDRAM DIMMS.

I've since bought 2x128Mb SDRAM modules (part number:
MT48LC16M8A2TG-75B, 8 chips per DIMM). However the memory check only
detects 32MB of RAM.

I'm now learning that there's memory density issues with this chipset.

What's the maximum memory I can expect to get this board up to? Do I
go with EDO or SDRAM and what caveats should I be aware of when
looking for suitable memory? Ideally I'd like to get it working with
256 MB of RAM.

Thanks,
Jonathan

 

[Larry]

I was recently given an old PC which I'm looking to upgrade and give
to my uncle.

The bios boot-up string is: VxPro-UMC8670-2A5LAH09C-00.

I tracked down a motherboard manual for the PM-8600 and while the
layout is not quite the same it's very similar.

Looking in that manual it suggests that the board can take up to 128
MB of EDO DRAM SIMMS and up to 256 MB of EDO DRAM/SDRAM DIMMS.

I've since bought 2x128Mb SDRAM modules (part number:
MT48LC16M8A2TG-75B, 8 chips per DIMM). However the memory check only
detects 32MB of RAM.

SSounds about right. Tried to update an older board a couple of years back
that used EDO. EDO uses a different paging of memory module so that the
SDRAM was only detected at about 1/4 of what the package said but it still
worked.

Larry

 

[JAD]

put in only one stick and if it does not show its size correctly(128)
move to another slot.
I would have gone the same way as you in regards to using the SDRAM
rather than edo.
just based on the speed.

 

[steven67@]

I was recently given an old PC which I'm looking to upgrade and give
to my uncle.

The bios boot-up string is: VxPro-UMC8670-2A5LAH09C-00.

I tracked down a motherboard manual for the PM-8600 and while the
layout is not quite the same it's very similar.

Looking in that manual it suggests that the board can take up to 128
MB of EDO DRAM SIMMS and up to 256 MB of EDO DRAM/SDRAM DIMMS.

I've since bought 2x128Mb SDRAM modules (part number:
MT48LC16M8A2TG-75B, 8 chips per DIMM). However the memory check only
detects 32MB of RAM.

I'm now learning that there's memory density issues with this chipset.

What's the maximum memory I can expect to get this board up to? Do I
go with EDO or SDRAM and what caveats should I be aware of when
looking for suitable memory? Ideally I'd like to get it working with
256 MB of RAM.

Thanks,
Jonathan

..


I believe you have the wrong motherboard manual.

Your motherboard is probably a PCChips M537, also sold as an Amptron
PM8400A/B. This board uses the VXPRO chipset (a relabeled VIA Apollo VP-1
chipset). This supports memory chip densities up to 16Mbit. This will
limit it to a maximum of 32MB per SDRAM DIMM. And these 32MB DIMMs must
have sixteen 16Mbit chips. Two 32MB SDRAM DIMMs could be used for a total
of 64MB. Two 64MB EDO DIMMs may be possible, for a total of 128MB; but
each 64MB EDO DIMM must have thirty-two 4Mx4(16Mbit) chips.

Check the PCChips Lottery for more info:
http://www.stud.fernuni-hagen.de/q3998142/pcchips/index.html

 

[Jonathan Lonsdale]

Your motherboard is probably a PCChips M537, also sold as an Amptron
PM8400A/B. This board uses the VXPRO chipset (a relabeled VIA Apollo VP-1
chipset). This supports memory chip densities up to 16Mbit. This will
limit it to a maximum of 32MB per SDRAM DIMM. And these 32MB DIMMs must
have sixteen 16Mbit chips. Two 32MB SDRAM DIMMs could be used for a total
of 64MB. Two 64MB EDO DIMMs may be possible, for a total of 128MB; but
each 64MB EDO DIMM must have thirty-two 4Mx4(16Mbit) chips.

If I go with 72pin SIMMS i.e. 4x32MB EDO to get 128MB are there any
particular kind of SIMMs I need to go for or should any do. I.e. are there
memory density issues with the SIMMs too?

 

[steven67@]

If I go with 72pin SIMMS i.e. 4x32MB EDO to get 128MB are there any
particular kind of SIMMs I need to go for or should any do. I.e. are there
memory density issues with the SIMMs too?

..


You will need non-parity 32MB SIMMs with sixteen 16Mbit chips. If you are
running a 66 MHz or faster bus speed, you will want 60ns or faster memory (lower
numbers are faster).