Compaq Presario new RAM "164 - Memory Size Error"

I have attempted to upgrade the RAM in a Compaq Presario desktop PC, and am made aware of a POST message code that appears right near the start of POST.

The system boots OK with the single 64MB stick of PC100 memory, but fails to get past POST with 2 x 256MB PC133 memory.

The error message "164 Memory Size Error" shows regardless which memory is installed, but it's just that the hang at POST with the new memory allows me to see this on screen.

http://www.uktsupport.co.uk/compaq/faq/comppost.htm

States that a "164 - Memory Size Error" should be accompanied by 2 x short beeps and identifies the cause as "Memory Config Incorrect", and suggests "Run Computer Setup".  There are no beeps, but I forgot to check the internal speaker connection, and I seem to recall that it doesn't give the "started OK" single beep, so it probably is beeping at me.

Crucial.com, however, state this in their FAQ (http://www.crucial.com/uk/kb/Answer.asp?qid=3905):
 
Q: When I installed my memory my computer displayed a "164 memory size error."

A: Don't worry about it. Some computers show this message whenever memory is added or removed. There is no cause for concern, and the message will disappear the next time you boot up your system.

The problem is that this F10 CMOS Setup Screen doesn't have any memory-specific settings to change.  I will need to look into this further, and perhaps see if it is running the CMOS Setup from a non-DOS F10 diagnostics partition as with some of the older Compaq's.

When I change the memory back and forth, the BIOS DOES detect the change, and counts through it up to the correct RAM capacity (minus the 1MB of shared video memory - it also has a whopping 4MB on-board video memory all to itself!!).

Compaq Presario 5BW120 Desktop PC - Product Specifications:

http://h10025.www1.hp.com/ewfrf/wc/document?lc=en&cc=uk&docname=c00032396&product=93660&dlc=en&lang=en

Intel i810e Motherboard Memory Spec's:

2 x memory slots - use one or both with SDRAM
Min 16MB (i810 board needs 64 MB due to on-board graphics)
Max 512MB
Type 3.3 v 168 pin SDRAM DIMM 100 MHz unbuffered non-ECC (64-bit)
SPD (Serial Presence Detect) (BIOS recovery needs SPD).

Supports Single or Double-Sided DIMM's in the following sizes:

16MB  -  2 Mbit x 64
32MB  -  4 Mbit x 64
64MB  -  8 Mbit x 64
128MB - 16 Mbit x 64
256MB - 32 Mbit x 64

Note: If using 256MB modules, they must be built with 128 Mbit technology.

Crucial's Online Memory Configurator showed this as one of the compatible modules:

256MB CT283169 SDRAM, PC133 CL=2 Unbuffered Non-parity 3.3V 32Meg x 64

http://www.crucial.com/uk/store/MPartspecs.Asp?mtbpoid=808F4743A5CA7304&WSMD=Presario+5000+Series+Model+5BW120&WSPN=CT283169

So the 133 MHz really isn't an issue here but I'm puzzled about the note in the Intel i810e pdf manual about the "128 Mbit technology" requirement for 256 MB modules indicated above.

Any idea what they mean by that?

The single SDRAM DIMM that WAS fitted before, and with which the system booted OK but still showed that "164 memory Size Error at early POST, was:

Micron Tech. 4LSDT864AG-10EB1
64MB unbuffered 64-bit non-ECC PC100 SDRAM

The 2 x 256 MB modules I have fitted, and on which the boot halts at POST, are the same spec (as far as I am aware), except the speed.  They are a couple of modules branded for a large computing outlet based in the UK, but I don't have them with me to check the number of chips, etc.

Of course, the notes above about what RAM is accepted is taken from the INTEL documentation relating to an Intel branded i810e board, and not the Compaq one used in the Presario 5BW120 C/600/E model.  This falls into the Presario 5000 Series, but the motherboard is reported by diagnostics utilities as Whitney 910e just the same.

The Compaq motherboard model is 06C0h, and the current BIOS version and date are Compaq (07/24/00) version 686C3.

The latest Compaq BIOS update would upgrade it to 2001-07-20 (1.05 Rev. A), but the list of fixes in that (and included from previous versions) does not address any issues about memory.

http://h10025.www1.hp.com/ewfrf/wc/softwareDownloadIndex?lc=en&lang=en&cc=uk&os=20&product=93660&dlc=en&softwareitem=33678

The only useful features, for which I am tempted to flash the BIOS, are:

- Added F10 Setup Detect Drive feature for IDE and floppy drives
- Enhanced USB legacy handoffs
- Improved USB support in DOS and Windows safe mode
- Enhanced boot options in BIOS setup
- Changes memory buffer strength for configurations of two double sized memory modules

Do you think that last fix might be relevant?

The 2 x 256MB modules I am trying to use in the system are double-sided, but I'm not sure that I understand the "memory buffer strength" expression.

Running the Microsoft Memory Diagnostics utility from boot CD seems to freeze indefinitely after about the 3rd test of 7, which tends to imply  faulty memory, but I would have thought this would have issued a different error code like: 201 or 203 - Memory Address Error (RAM Failure Replace Memory) as listed here:
http://www.uktsupport.co.uk/compaq/faq/comppost.htm
A "parity error" would also issue a different code.

I intend to test the memory on my own PC (Pentium 4 board), but can only get back to the PC in a couple of days.

Any suggestions or comments will be appreciated meantime.