Win7 64-bit, 4gb RAM - only 3.5gb showing - help!


I have a Foxconn 520A with the latest firmware. In post it reports 4096MB installed.

Windows 7 Ultimate 64-bit and Ubuntu can only see 3.5GB however. The memtest option which Ubuntu installed only reports this as well. This is brand new Samsung RAM which I have just installed, checked for errors and none found.

Any ideas anyone? There are no options for memory remapping or anything of the like that I can see in the BIOS - perhaps there's a hidden menu somewhere that I cannot see... I've tried Ctrl+F1 and variations but nothing doing :/
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  1. I should add that the mobo specs from Foxconn explicitly state that 4gb RAM is supported across the two slots - which is what I've got installed.
  2. Are you absolutely certain you have Win 7 64bit installed? What you are reporting sounds exactly like what I'd expect from a 32bit operating system.

    If you had Win 7 32bit, and Ubuntu 32bit, then that would explain seeing only 3.5GB.
  3. I am absolutely 100% certain - no doubt about it, both Windows and Ubuntu on my machine are 64-bit.

    I did just look at DxDiag as I remembered it has more info in there... the Approx Total Memory for the display is showing at 1830MB so I'm wondering whether the GFX card is somehow sharing system memory... I have no settings anywhere in the BIOS to change that though :/

    I just put these two 2GB sticks in today, previously I had 2x 1GB sticks in there and there was no drop in the available memory from 2GB to something lower, so I don't know why it is just suddenly doing it now.
  4. ive only got 3.5 gb showing on my win7 64bit, im sure it because the system reserves 512mb for its self...but i dono.
  5. See if your bios has an option to remap memory.. Something like "Memory remap feature", if it's disabled your system will only use 3.4GB. My mobo has this feature.
  6. Sure vga onboard ?
    512 for sharing memory vga also check setting memori remap in bios enabled
  7. I agree with Memory Remapping as the probable cause, the MCP68D-S chipset didn't seem to have 32-bit limitation.

    For >4GB the OS & CPU must be 64-bit, the MOBO requirements are a 48-bit or 64-bit chipset, and the BIOS has to support 64-bit memory mapping. Set 'Memory Mapping {Remapping} -> Enabled.

    Also see ->
  8. I just googled "Foxconn 520A memory remap" and lot's of things showed up. Lots of users with foxconn boards have this problem and the bios doesn't even have the option to remap memory, although the specs clearly say it supports 4gigs or more on some models. Let's see what's your case..
  9. Then live with 3.5GB there's no other magic. Anytime I see a 4GB limitation MOBO I suspect to see this exact problem.
  10. Yeah - it's one of those mobos which is troubled through and through from lack of support and drivers to missing features in the BIOS etc. I'll be glad when I'm shot of it!
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