HP Vectra 1.2 GB Ram reporting 768 MB Ram Only - HELP!

[quantass]

I own an HP Vectra VL800/1700 PC (1.7 GigHZ), HP WMTA System Board, HP CDWriter Plus, DVDROM, and using Win2000Pro. Presently I have 1.2 Gigs of Ram installed within the 4 RIMM slots -- 2- 512 Megs sticks, 2- 128 Megs sticks (4 sticks in total). Unfortunately BIOS POST and Win2000 Pro report that I only have 768 Megs of Ram in total. I launched SiSoft Sandra and it reported that I have:
Bank 1 - RIMMA1 RIMM RAMBUS DRAM 128MB/16
Bank 2 - RIMMA2 RIMM RAMBUS DRAM 256MB/16
Bank 3 - RIMMB1 RIMM RAMBUS DRAM 128MB/16
Bank 4 - RIMMB2 RIMM RAMBUS DRAM 256MB/16

Maximum installable Memory: 2GB

I took a peak inside and saw that the 512 Meg sticks were labeled as: Kingston KTH VL800/512 698443 K2. I have 512 Meg sticks not 256 Meg sticks. What happened? Where's the rest of my memory?

[jeiworth]

I'm not really sure, but I think Bank 1 & 2 and respectively 3&4 must be equipped with the same sticks, e.g.
Bank1 512MB
Bank2 512MB
Bank3 128MB
Bank4 128MB

[BigBlue66]

Nope, I have the same system and the RAM is installed correctly.

When you installed the new RAM, did you go into BIOS setup? If not, try that, even though it might be claimed that the board will automatically detect the memory.

So just go into BIOS setup, F2 I think, but don't change anything. Just Save and Exit. This will hopefully write the new memory amount to BIOS.

If this works, let me know, because I'm looking to install additional RAM on my exact same system.

Cheers.

[BigBlue66]

Oh and here's another idea. Install the largest memory modules in the first bank that the system reads from, which I think are 1 and 3. So pop the 512 sticks in there and the 128's in 3 and 4. Again, please post back with your progress.

[quantass]

Ok, I tried entering BIOS and saving but the memory remains 768 MB. I also tried swapping the memory sticks so that instead of:
Bank 1: 128MB
Bank 2: 512MB
Bank 3: 128MB
Bank 4: 512MB

I altered them to:
Bank 1: 512MB
Bank 2: 128MB
Bank 3: 512MB
Bank 4: 128MB

but I still get the same problem -- 768 MB total memory. I went to HP's site and found some information about the mobo. It appears that one must have Bank sets 1 &3 and Bank sets 2 & 4 exactly match one another in size and speed. So my above configurations are fine but any other order will screw everything up. And I am unable to leave ANY slots empty to avoid system failure. This truly is the strangest mobo I've ever seen. Picky picky. If I didnt know any better I'd say the slots were capable of only 256MB memory max and not the much documented 512MB.

Any other suggestions on getting my remaining memory detected?