• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Weird RAM fault

I have 4 x 4gb ddr3 ram modules fitted to my desktop.

I have started to find that the amount the system recognises seems to change of its own accord.

Yesterday i started my machine and my system reported 16 GB installed but only 12 useable.

I then had to do a restart due to a windows update and it then said 16GB installed and 16GB available.

I have just started my system and it now says 12GB installed but only 8GB useable.

I think it may be a faulty module that works when it sees fit. But with it now saying 12 installed and only 8 useable I'm not sure.

I have attached a shot of the system info screen and resource monitor from now.

Any help, ideas, tips would be appreciated.



My Computer

System One

  • OS
    Windows 8 pro 64 bit
    System Manufacturer/Model Number
    Home built
    AMD fx 8120 8 core
    asus M5A78L-M USB 3
    16 GB
    Graphics Card(s)
    ASUS gtx560Ti


New Member
Just to show what I mean, not 10 minutes later after a restart we are now back to 16Gb available.
Based on the two images in your previous posts, it isn't likely that this a RAM fault; both images show 16GBs memory in total. One image shows about 12GBs available and 4GBs of hardware reserved, the other image shows 16 GBs available and only 18MBs for hardware reserved.

Hardware reserved memory allocation is controlled by the BIOS, or UEFI, and not available for Windows but reported nonetheless. You should look into the BIOS how much memory is allocated for various hardware and change it, if available. Alternatively, a BIOS update usually resolves excessive memory reservation.

It is also possible that you have some flash device(s) connected at boot time, that request 4GBs memory reserve for its operation. This would be easy to test, just disconnect the flash device prior to booting and check the memory utilization.

My Computer

System One

  • OS
    Win 8.1
    Computer type
    System Manufacturer/Model Number
    Dell Latitude
    Intel i5-3350P (3.1 GHz)
    16 GBs
    Graphics Card(s)
    AMD Radeon HD7850
    Sound Card
    Built-in to MB
    Monitor(s) Displays
    2 x 24" Dell
    Screen Resolution
    3,840 x1,200
    Hard Drives
    128 GBs, OCZ Vertex, SATA III SSD
    256 GBs Intel SATA III SSD
    3 x Seagate 1 TBs HDD
    Antec 750W
    Antec P185
    Internet Speed
    50 Gb/s
    IE11, Firefox22.0
    Other Info
    Works, most of the times unless Microsoft patches decide otherwise...