128meg DIMM recognized as 32meg one

Recommended by Wim's BIOS...

I have a P5VX-BE Rev:3.0 motherboard wich supposedly supports up to 256MB RAM. BIOS is Ver 1.4a from 05/12/97.

I upgraded 4 16meg SIMMs to a 128meg PC100 DIMM. On boot it recognizes only 32MB

Any idea how can this be corrected? I saw a version 1.4h of BIOS, do you think flashing it might help?

I am kinda reluctant to do the flash thing: I never tried before.

[Denniss]

Hardware problem - explanation in the FAQ here .

You said check-out the FAQ for this 'hardware problem' I cannot find it!!

[Rainbow]

In the Wim's BIOS FAQ, not in FAQ of this forum

Thanks: at least I see this problem is well understood, even if it has no real solution (other than a new motherboard!)

The WimsBios FAQ reply says:
"The Intel VX doesn't have enough Memory Address lines to drive the higher integration DRAM technology, be it EDO
or SDRAM. 16-MBit is the highest density supported, while the parts on a 64-MByte EDO SIMM are 64-MBit (eight
chips)..."

But Denniss suggested I just use SIMM instead of DIMM. Why? The FAQ reply implies that the "16Mbit/chip" maximum applies for both SIMM and DIMM. Is this correct?

[KachiWachi]

The VX chipset will support 128MB SIMM Maximum, so the most you can put in is 4 32MB SIMMS. The DIMMS it can support only came in up to 32MB size before newer technology came out (that I am aware of), so if you have 2 DIMM slots, the most you can put in is 64MB. You can get the special 16-chip DIMMS but they are expensive. So you are better off finding the 4 SIMMS and installing those. That is what I'm running, and each SIMM (if I remember correctly) contains 16 chips (8 per side).

See http://sysopt.earthweb.com/intelchip.html for more info.

[ajzchips]

I suppose you meant the special, double-height, 32-chip, DIMMs.

[quote="KachiWachi"]...So you are better off finding the 4 SIMMS and installing those. That is what I'm running, and each SIMM (if I remember correctly) contains 16 chips (8 per side).

I'm still not sure whether you answered my question regarding the 16Mbit/chip addressing limit. Most 32Mbyte SIMMs are described as 8x32. Is this suitable?
See for instance the good price at http://www.comtread.com/32mb72pinedo.html.
Would these be OK for me??

[ajzchips]

I've had those working just fine on an old PCCHIPS VX board (same chipset). The ones I used had 4 chips on each side (total of . The one you pointed out have at least 8 (can't see the other side), so it should work.
BTW, the NANYA brand of chips is one of my favorites for EDOs

[KachiWachi]

See this for what the VX chipset can support and why (from Intel) http://www.intel.com/support/chipsets/4 ... ATDN7V.HTM.

Last time I looked you could still get the DIMMs from Kingston (ValueRAM); ask for P/N KVR100X64C216/32 (16 chip, i430VX Chipset). I have the .pdf datasheet, if you want it.

AJZ -- Never saw the double-height 32 chip DIMMS...have you??? Did they really exist?

[ajzchips]

Here's a scan of both sides of the DIMMs (I have two of them).

[KachiWachi]

WOW...

And this is a 32 or a 64MB DIMM??

And a question...in that Intel document...do they mean the DIMM itself or the chips on them to the 4Mx8 limitation??

[ajzchips]

64MB.

The limit is both technological (X*Y layout) and physical (total number of chips).

[KachiWachi]

...and it is SDRAM...right?

Could you provide the chip ID numbers just for reference??? I'm curious now...

[ajzchips]

Yes, SDRAM.

On the chips of one stick:

NEC JAPAN
D4516421G5
-A10-7JF
9802LY004

On the chips of the other:

F JAPAN
81117422A-100FN
9650 M55

BTW, strange enough, these DIMMs are better recognized on the older i430VX chipset than on the newer ones.

i.e. the PCCHIPS M520 I used to have would recognize the full 64MB capacity of these sticks, but were slightly unstable because of the high power draw (I suppose). Newer chipsets will either recognize only 32GB or not detect them at all. Weird...