Member Avatar for j3k2

Hi everyone! I wanted to install new ram on my MSI955X Platinum Mobo. The existing ram is 3GB. The mobo has 4 slots (dimm1, dimm2 and dimm4) and can be ugraded up to 8gb. I bought a 2GB DDR2 667 mhz but when I installed the ram, it doesnt detect the new memory. I thought it has modules configuration so I inserted another 1GB to fully utilized the slot but the problem is still there (dunno what i am doin' wrong). My total ram are as follows 2GB, 2GB, 1Gb and another 1GB. Please help.

  • 2 Contributors
  • 4 Replies
  • 228 Views
  • 1 Day Discussion Span
  • Latest Post Latest Post by j3k2

Dani AI

Generated

Follow the motherboard documentation first — that usually answers this exact symptom.

The MSI 955X Platinum (MS‑7158) user manual and MSI listings show this board is limited to 4 GB total (and the manual documents per‑DIMM / population rules rather than 2 GB per slot). That explains why the new 2 GB DDR2 stick wasn’t detected: the board revision you have appears to expect 1 GB DIMMs and specific slot/pair combinations, even though the Intel 955X chipset itself can be used in designs that reach 8 GB. ()

Quick, practical checks (in roughly this order):

  • Power down, remove the new 2 GB stick and boot with only known 1 GB sticks; confirm BIOS reports the expected memory.
  • Test the 2 GB stick by itself in one slot (and, if possible, in another machine) to rule out a faulty module.
  • Populate slots as the manual prescribes (matched pairs, color‑coded slots) — do not run with three mismatched sticks.
  • Verify the modules are unbuffered, non‑ECC DDR2 1.8 V (the board requires unbuffered DDR2). If BIOS never sees a lone 2 GB stick, it’s a compatibility/size limit. ()

About the OS: running Windows XP Pro 32‑bit will still only show up to 4 GB of physical address space and typically ~3–3.5 GB usable because of device memory reservations; to actually use more than ~4 GB you need a 64‑bit OS (and a board/BIOS that supports remapping). Your Pentium D CPU family is 64‑bit capable, so a 64‑bit Windows install is possible if the hardware supports the larger DIMMs. (learn.microsoft.com)

Options to resolve this quickly:

  • If the manual limits each slot to 1 GB: install four 1 GB sticks (max 4 GB) or replace the motherboard with one whose manual/QVL lists 2 GB-per-slot support.
  • Update BIOS only if MSI explicitly lists a revision that adds larger‑DIMM support; otherwise buy modules that match the board’s documented limits. ()

Notes: , as suggested, check BIOS first (and a tool like CPU‑Z) to see what the hardware actually reports before buying more RAM.

Recommended Answers

All 4 Replies

Member Avatar for The New Normal

Well, the first thing that comes to mind is; what operating system do you use? Is it 32bit or 64bit?

A 32bit O/S cannot address more than 3.5GB of RAM. So if your graphics card takes the .5 that only leaves 3GB. Any more will not show up in windoze.

You can still, however, check that it's detected but not used. CPUZ and the BIOS should both show the total RAM. For simplicity I'd get CPUZ from here (d/l in top left hand corner, it's free) and see if it's detected, just not used.

If you are using 64bit there may be a problem (like an old BIOS or something) but we'll cross that bridge if/when we come to it.

Member Avatar for j3k2

thanks for the reply! I am using xp pro 32 bit. Can i install a 64 bit os? What are the requirements? My pc is a running on pentium d 3.0

Member Avatar for The New Normal

Yeah you can install a 64bit o/s, your CPU supports it. A compatible CPU and motherboard are the requirements.

I can't give o/s recommendations, as people's experiences vary so much. Some love this and that, others hate it.

I've never used XP-64 but I hear in can be difficult to find drivers for obscure things, like webcams etc.

I use Vista-64 and have never had a problem but I don't have lots of extras (like printers, webcams etc.) so I've not really thoroughly tested it.

commented: his been a big help and very straightforward, he solved my problem quickly +1
Member Avatar for j3k2

thanks The New Normal, you'd been a big help!

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.