Windows – 3GB RAM Installed and Detected by BIOS, Windows Vista 32bit Only Sees 2GB

32-bitmemorysupermicrowindows-vista

I am attempting to install more RAM on a Windows Vista 32bit machine which is using a X6DAL-XG motherboard and the RAM amount reported in the BIOS is 3GB+, but Windows is only reporting 2GB installed. The motherboard has 6 RAM bays which I have populated with various combinations of 4 1GB sticks, and 2 512mb sticks, but no matter how I configure them Windows doesn't see more than 2GB. I realize of course 32-bit Windows has a 3gb cap on memory, but that doesn't explain why it will only report 2GB when there are in fact (currently) 5GB installed. I should think I would be able to see at least 3GB.

According to the spec list for the motherboard the minimum RAM requirements are DDR333/266mhz installed in pairs. I have done this exactly, and the BIOS isn't reporting any problems at POST.

RAM Configuration (according to CPU-Z)

  • Slot #1: PQI MD6412ROE – 512mb PC2700 (166mhz)
  • Slot #2: PQI MD6412ROE – 512mb PC2700 (166mhz)
  • Slot #3: Kingston 128mx72D266C25 – 1024mb PC2100 (133mhz)
  • Slot #4: Kingston KVR266X72RC25/1024 – 1024mb PC2100 (133mhz)
  • Slot #5: Kingston 128mx72D266C25 – 1024mb PC2100 (133mhz)
  • Slot #6: Kingston KVR266X72RC25/1024 – 1024mb PC2100 (133mhz)

I'm not sure if memory specs above conflict with this statement in the motherboard manual or not:

Memory Support

The X6DAL-XG supports
up to 12GB/24GB of registered ECC
DDR333/266 (PC2700/PC2100) memory. The
motherboard was designed to support
4GB (PC2100) modules in each slot, but
only the 2GB modules have been tested.
When using registered ECC DDR333
(PC2700) memory, installing four
pieces of double-banked memory or six
pieces of single-banked memory is
supported.

So, am I doing something wrong with the RAM I have now, or is there some sort of compatibility problem which I am missing?

Thanks!

A Few More Details

  • CPU-Z report for the machine
  • I have run some additional tests with
    this issue in both Ubuntu and Windows
    Server 2008 and they are both
    reporting only 2gb as well.
  • I tried fiddling with the Memory
    Remap feature (Enable/Disable) in my
    motherboard's Northbridge
    configuration, but did not see any
    results.
  • In addition to the hardware above, I
    have one 256mb PCI Express video card
    and that's it for peripherals. I do
    not think memory mapped I/O is the
    issue here.
  • I have removed the 2 512mb sticks
    and I'm down to just the 4 1GB sticks
  • I have flashed the motherboard BIOS to
    the latest manufacturer revision

Another Update

I have managed to test this hardware configuration on a 64-bit copy of Ubuntu and the RAM is being fully detected at 4gb installed, but no matter the RAM configuration I am unable to find any 32-bit OS that will read more than 2gb. So the question remains: Why can a 64-bit OS see more than 2gb of RAM while a 32-bit OS installed on the same machine is capping out at 2gb?

After Thoughts

I greatly appreciate the input from everyone however, I still do not feel there has been a correct answer to this problem yet despite all of your efforts. I did learn, thanks to @Goyuix, that I have been using a 64-bit CPU and didn't even realize it and so now at least I have an acceptable work around.

Barring some unexpected turn of events it looks like the bounty is going to be auto-credited to @Mark Booth due to the bounty expiration, which I don't necessarily mind because his answer is good; it just isn't the solution to this particular problem. (Absolutely no offense intended Mark, I really appreciate your high quality answer!)

In any case, the discussion generated by this question has been extremely informative for me (and should act as a great reference material for future searchers). The original problem has been successfully mitigated through the use of a 64-bit OS, but it still has not been solved. Unfortunately (for me), I'll never be truly content until I can pinpoint the exact problem, so if at some point in the future someone manages to think of a solution that hasn't been mentioned, please, please do post it.

Thank you everyone.

Best Answer

Since you mentioned in a comment that Server 2008 is only reporting 2 GB, then something is very wrong with your configuration.

  1. What does your BIOS report for installed RAM? Does it see 4 GB?
  2. According to the manual:
    • Memory Remap must be Enabled
    • Memory Mirroring must be Disabled
  3. How are your modules installed? The manual specifies that they have to be installed in pairs, and that the paired slots are adjacent to each other. According to your post, it looks like you don't have your paired ram installed into adjacent slots. Verify the physical installation of your modules against the motherboard manual/motherboard imprinting.
  4. Have you tried each pair of 1 GB modules individually?
    • If so, test each pair with Memtest86+ to ensure that each pair works correctly.
    • If each pair checks out, try changing the order they're installed in.
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