Trouble with AGP Aperature subtracting from 4GB RAM size

By alcratin_42
Oct 18, 2003
  1. I built a powerhouse system for music production. P4 3.0 GHz, 4 GB RAM (Gigaram), XP Pro SP1, tweaked for music production. Tried both I-Will P4HCT and ASUS P4P800-Deluxe mobo's.

    When an ATI 9800 is installed the mobo will subtract 512 MB of
    available memory from system RAM.

    When an Nvidia GeForce 4400 is installed, the mobo will subtract 256 MB of available memory from system RAM.

    This is viewable during the POST test and is reflected in System Properties in the OS.

    If I pull 1 GB of RAM (1 stick) and run the system with 3 or even 2 GB, this does not occur.

    Somehow the memory controller does not allow the aperature size to be removed from the system when memory is maxed out.

    I've referenced Wiley's publications for reference to this. I'm still contacting IWill and ASUS about this for more info. And it's obviously not a common problem because hardly anyone loads the system down with full memory (at $300 per stick!!!! for the good ram, not the cheap stuff (

    Apparently Windows XP itself has a 4 GB RAM limit too, before needing to use Windows 2003 Server which will handle more apparently like 8 or 12 GB. But even I don't have that kind of money, those RAM requirement use registered RAM, and those types of boards don't recommend Kingston or Viking at all.

    Anyone have any ideas? Before I need to go buy a server board to get 4 GB of RAM that is fully accesible?

  2. ---agissi---

    ---agissi--- TechSpot Paladin Posts: 1,977   +15

    Sorry I dont know why it would do that.. maybe P66 or Rick would know. However, why go buy a server board? You could use 3GB. Is that extra 1GB really essential enough for you to have to go get a server board? *Just wondering*
  3. alcratin_42

    alcratin_42 TS Rookie Topic Starter

    Yes, I need the 4GB of RAM.

    The program I am using caches all the sample libraries to RAM, not from the HDD, they will support that in the future, but we need the ability to dump the samples to RAM.

    East-West Quantum Strings 27GB String Lilbrary for Film Scoring.
  4. Spanky76

    Spanky76 TS Rookie

    Addressing maxed out

    Your system can address 4 gig of memory maximum. When the system memory uses all of this space, some must be de-allocated to make room for the AGP aperture. When using less system memory, the AGP aperture is simply placed above it (up to the 4g limit).

    Sorry, I meant to say the video memory gets mapped into the 4 gig space, not the AGP aperture. (It's early, and I haven't had my coffee yet). This would seem to make sense if your GeForce 4400 has 256 meg of addressable memory and the ATI has 512 meg.
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