HP Compaq DC5100 Has 4 GB of RAM installed but 3.12 GB of RAM is only used

Hello guys! I'm having a problem with my HP Compaq DC5100, The problem is, I have 4 GB of RAM installed but only 3.12 is used in Windows 7. Here are the specs:

HP Compaq DC5100 SFF (Model number: EW744LA)
4 GB RAM (Using 4 1 GB sticks)
Intel Pentium 4 HT 651 Cedar Mill 3.40 GHz
80 GB hard drive
Windows 7 Ultimate
Intel(R) 82915G/GV/910GL Advanced Graphics v3.5

So i think something in the Hewlett-Packard 786C2 BIOS has something enabled in the BIOS setup that makes Windows only using 3.12 GB RAM out of 4 GB of RAM installed.

Comments

  • 32-bit or 64-bit version of Windows? The 32-bit can use up to 4GB (3.5 usable). However, your system is using the integrated GPU, which that takes most of the RAM as well.

  • its the integrated GPU probably taking 512 MB, maybe more

  • You are very likely using Windows 7 x86, where system components such as graphics (even discrete graphics cards) are mapped into the memory space below 4 GB by the BIOS, which eats into the area of memory usable for the kernel and software. (or something like that)

    As such, on older hardware you will only be able to use roughly 3.1 GB with an x86 OS, then with newer hardware (like 900 series GeForces, Skylake era etc.) you may find yourself with as little as 1.5 GB usable.

    The solution is to either switch to an x64 OS or use an x86 OS that supports PAE (Physical Address Extension) like Windows Server 2000-2008 (client Windows needs to be patched and is not licenced to use more than 4 GB). The latter may not be worth it with only 4 GB though.

  • @Windows7User2010 said:
    32-bit or 64-bit version of Windows? The 32-bit can use up to 4GB (3.5 usable). However, your system is using the integrated GPU, which that takes most of the RAM as well.

    @win32 said:
    You are very likely using Windows 7 x86, where system components such as graphics (even discrete graphics cards) are mapped into the memory space below 4 GB by the BIOS, which eats into the area of memory usable for the kernel and software. (or something like that)

    As such, on older hardware you will only be able to use roughly 3.1 GB with an x86 OS, then with newer hardware (like 900 series GeForces, Skylake era etc.) you may find yourself with as little as 1.5 GB usable.

    The solution is to either switch to an x64 OS or use an x86 OS that supports PAE (Physical Address Extension) like Windows Server 2000-2008 (client Windows needs to be patched and is not licenced to use more than 4 GB). The latter may not be worth it with only 4 GB though.

    I do indeed use Windows 7 x86 in my HP Compaq DC5100

  • @win32 said:
    You are very likely using Windows 7 x86, where system components such as graphics (even discrete graphics cards) are mapped into the memory space below 4 GB by the BIOS, which eats into the area of memory usable for the kernel and software. (or something like that)

    As such, on older hardware you will only be able to use roughly 3.1 GB with an x86 OS, then with newer hardware (like 900 series GeForces, Skylake era etc.) you may find yourself with as little as 1.5 GB usable.

    The solution is to either switch to an x64 OS or use an x86 OS that supports PAE (Physical Address Extension) like Windows Server 2000-2008 (client Windows needs to be patched and is not licenced to use more than 4 GB). The latter may not be worth it with only 4 GB though.

    Do i must patch Windows 7 x86 to support PAE?

  • It's a violation of the Windows 7 licence so I won't tell you how to but yes. Apparently some x86 drivers may not take very well to components being mapped beyond 4 GB which is why Microsoft doesn't put support for it (the memory extensions) in the client Windows OSes. XP SP0 actually does have full PAE support but it was disabled in SP1.

  • @win32 said:
    It's a violation of the Windows 7 licence so I won't tell you how to but yes. Apparently some x86 drivers may not take very well to components being mapped beyond 4 GB which is why Microsoft doesn't put support for it (the memory extensions) in the client Windows OSes. XP SP0 actually does have full PAE support but it was disabled in SP1.

    @win32 said:
    It's a violation of the Windows 7 licence so I won't tell you how to but yes. Apparently some x86 drivers may not take very well to components being mapped beyond 4 GB which is why Microsoft doesn't put support for it (the memory extensions) in the client Windows OSes. XP SP0 actually does have full PAE support but it was disabled in SP1.

    I PAE patched Windows 7 but it didn't worked as the system properties still says that 3.12 GB is only used. So i uninstalled the patch.

  • edited November 30

    I heard that the PAE patch for 7 provides two boot options, one PAE and another non-PAE. Did you check for boot options in msconfig to see if the PAE option was hidden? But again, with the integrated graphics, a certain amount of memory may still be mapped to it. I know that when I did Server 2003 PAE with 4 GB RAM, I had nearly 4 GB in system properties but a virtualized Windows 2000 Advanced Server with 8 GB RAM only showed somewhere around 7-7.5 GB.

    You should be better off running 7 x64, with DOSBox for any DOS/win16 programs using Windows 3.1x. I have Vista SP2 x64 on an early C2D with 4 GB of RAM and it performs impeccably; both 64-bit Vista SP2 and 7 SP1 idle at about 800-900 MB on a clean install. I believe that Cedar Mill P4s have x64 support.

  • edited November 30

    I had an Acer laptop once that shipped with 4GB RAM and Vista 32 bit so I had the same issue as you. I thought it was odd that they didn't just put the x64 version on it so it could utilize all the memory that they had designed it with. Anyway, I upgraded it to Win7 x64 and then I was able to use all 4GB. It even ran faster and more stable than it ever did with Vista 32 bit. :-)

  • @win32 said:
    I heard that the PAE patch for 7 provides two boot options, one PAE and another non-PAE. Did you check for boot options in msconfig to see if the PAE option was hidden? But again, with the integrated graphics, a certain amount of memory may still be mapped to it. I know that when I did Server 2003 PAE with 4 GB RAM, I had nearly 4 GB in system properties but a virtualized Windows 2000 Advanced Server with 8 GB RAM only showed somewhere around 7-7.5 GB.

    You should be better off running 7 x64, with DOSBox for any DOS/win16 programs using Windows 3.1x. I have Vista SP2 x64 on an early C2D with 4 GB of RAM and it performs impeccably; both 64-bit Vista SP2 and 7 SP1 idle at about 800-900 MB on a clean install. I believe that Cedar Mill P4s have x64 support.

    And also, After i uninstalled PAE patch, I removed 1 stick of 1 GB of RAM and replace it with one 512 MB RAM stick and i still got the same error that says "3.50 GB (3.12 GB usable)" so i left no choice but to stick with 3 GB RAM. So when i have 3 sticks of RAM, The BIOS Memory update says "3072 MB" but when i install 1 stick of 1 GB ram, it says "3200 MB" like this screen: https://www.lfs.net/attachment/129393

  • edited November 30

    https://support.microsoft.com/en-gb/help/978610/the-usable-memory-may-be-less-than-the-installed-memory-on-windows-7-b

    https://ark.intel.com/products/27712/Intel-82910GL-Graphics-and-Memory-Controller

    I remember tinkering with a server with 328gb ram. The system ram Server 2008R1 and later R2. The graphics card took 8gb of ram for itself, causing both the bios to report 320gb ram and windows to report only 320gb usable. The chipset on your computer is capable of allocating memory as it sees fit to the integrated graphics, abstracted from software. If there is more memory available, it will take a percentage more.

    Same with a Latitude XT. I had 3gb installed, but only 2.7 gb usable. Where did that ram go? Checked the video card properties and saw that 256mb ram was allocated.

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