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I recently installed 4 gig or ram into my 32bit vista box. I realize that I wont be able to use the entire 4 gig until I go to 64bit vista, but 2 gig wasn't enough and I figured I could use as much of the 4 gig as vista will allow until I upgrade to 64 bit.

When I installed the 4 gig of ram, all of my PCI cards, A second graphics card, a second NIC, and a firewire card, stop working. Looking in device manager, the error was "This device cannot find enough free resources that it can use".

I read that PCI cards need some of the addressable memory space to use for memory mapping? Is the problem I use it all up with my ram? If so, Can I reserve some memory for these devices?

My computer is a Dell Precision 390. It has the Intel 975X Express chipset and an Intel Core 2 6600 @2.40 GHz processor.

Update: Removing my second video card allowed the other two PCI cards to start working. I'm not sure why.

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What chipset/processor are you using? –  Daniel A. White Aug 24 '09 at 13:56

5 Answers 5

up vote 2 down vote accepted

It could be that your computer is set to prioritize RAM over allocation for the cards. I would go to the BIOS and change the setting of PNP OS Installed (it'll be different for every BIOS but the idea is that the OS can change the settings of your PCI cards). If it's set to disabled or off, enable it. This will let Windows change the settings of your cards and could allow them to work. If it is already enabled go ahead and disable it since it could be Windows that is reallocating things in the first place.

Neither change will harm your computer and can easily be set back.

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It doesn't look like my dell bios allows me to do this. –  user836 Aug 24 '09 at 18:34

I don't think this should be a problem, but it does really sound like a memory addressing problem.

You are right. PCI cards, video cards, etc all need to be mapped to that small amount of space that 32 bit provides.

Remove the extra RAM that you installed (ie go back to 2GB). If that fixes the problem, then it is definitely a mapping issue.

In some cases, updating your BIOS can fix the issue. However, the only sure-fire fixes are to either:

  1. Stick with 2GB RAM (assuming it works from above) until you upgrade your OS.
  2. Upgrade your OS soon. You can always check out the Windows 7 free test versions that are available until next spring to tide you over.

Definitely try updating your BIOS first, though, as I've seen some people say that it works.

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Switching back to the 2 gig does allow everything to work again. –  user836 Aug 24 '09 at 18:33
    
Since your BIOS doesn't support what Joshua said above, it sounds like you're stuck with 2GB until you upgrade your OS. Definitely check out the free Win7 beta versions, though. Glad we at least got everything working again. –  th3dude Aug 24 '09 at 18:39

Your problem is that the first video card is using the same resources that the second video card is requesting. You're probably getting Device Manager error code 12, for which Microsoft counsels to disable the conflicting device.

You can verify this in the device manager / Display Adapters : right-click on each video card, then Properties and check the Resources tab of both cards for conflict.

This problem won't be solved by going to Vista 64-bits.
Some advice I've found when searching:

  1. Update the video driver
  2. Upgrade or downgrade the BIOS (dangerous!)
  3. This might not apply, but BIOS changes to either (a) limit the AGP Aperture to 256MB, or (b) change the video Share Memory size.
  4. Move the video card to another slot, for new resources to be allocated.
  5. In this thread the solution was to edit the boot options by entering

    bcdedit /set CONFIGACCESSPOLICY DISALLOWMMCONFIG
    which can be undone by:
    bcdedit /set CONFIGACCESSPOLICY default

  6. Clean install of the O/S, since resources are allocated during the installation of Windows.

Needless to say, make sure you have good backups before doing any of the above.

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Also, a 32 bit PCI card can only see 2GB of ram, the system has to double buffer it to get the data to the other 2GB of ram. Remember that from your ISA SCSI cards and having more than 16MB?

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I don't know how much memory your displaycards have, but it is possible (though newer cards should be smart about this and not allocate all their memory directly) that they eat up all the available memory.

In 32bit Windows your memory address space is divided in two blocks. First block from 0 to 2GB is accessible for you applications. The range from 2GB to 4GB is reserved for the Windows kernel and device memory. All your devices usually require some memory to work and this is mapped into the 2GB - 4GB area. Displaycards also map their internal memory there. If you have 2 cards with 512MB memory in each, that would mean 1GB of that memory would be allocated to their needs. As the video memory on displaycards got bigger, they began to map only part of their memory to that 2GB-4GB area, atleast when running 32bit OS. So that shouldn't usually be a problem.

I would first try installing latest drivers for all devices and then try to boot with 4GB of RAM. If this doesn't work, upgrading to the latest BIOS might be worth a try, also you could try to go with smaller AGP Aperture -setting in BIOS as Drake suggested. And it never hurts to download Memtest to check that the memory isn't faulty.

You could also try to enable PAE, that would allow you to use all of your memory. Unfortunately there are some device drivers that won't work with this setting.

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