Installed 16GB memory, only 8 usable, please help!

Hey guys!
I need your help please!!

I've just built a new PC and have a 16gb 4x4gb corsair 1600mhz memory that is running on windows 7 Home Pre'.

The memory on the PC properties in windows show this: "16gb (7.99 usable)"

BIOS reports 16GB.
CPU-Z recognized all 4 slots and says I have 16GB. (although DRAM freq' 758Mhz if that supposed to be like it)
dxdiag reports 16GB as well.

I am 100% sure this is windows Home Premium as I recently installed it, and I've triple checked.
Task manager reports up to 8gb of actual memory in use.

My mother board supports up to 16 GB dual channel memory with max of 4gb in every slot.
It's an "MSI P55-GD80" ----> from MSI Official site: " Supports four unbuffered DIMM of 1.5 Volt DDR3 1066/1333/1600*/1800*/2000*/2133* (OC) DRAM, 16GB Max
- Supports 1Gb/ 2Gb/ 4Gb DRAM size
- Supports Dual channel mode."

I also ran msconfig , selected the Boot tab and opened the Advanced options;
The 'Maximum memory' box is unchecked.

why windows uses only 8 gb out of my 16 installed?!
I can't seem to find a solution!

Any ideas what I should do next?
10 answers Last reply
More about installed 16gb memory usable help
  1. Start -> Computer -> System properties (at the top)

    Does it say Home Premium for sure, or Home Basic?
  2. omnisome is right. If it's home BASIC it is limited to 8gb, if it is home PREMIUM it is limited to 16gb.
  3. omnisome said:
    Start -> Computer -> System properties (at the top)

    Does it say Home Premium for sure, or Home Basic?

    Yes sir, "Windows 7 Home Premium." :)
  4. Here's a picture of all the properties I ran on my Desktop:

    Uploaded with
  5. Try switching around the ram.
  6. Are all the ram cards being detected in your bios?
    Reset the settings of bios.
    First try out the default ram settings set by the motherboard. If it doesnot work
    Set the ram settings to the ram specified values or just enable XMP.
  7. I tried switching the ram around already, what I haven't tried yet and will soon when I finish work here is to put 2 slots of ram at a time see what it does if I only have 2x4gb at a time. I will be trying it soon and let you know the results both from the BIOS and the OS.

    About setting XMP. Is this the Extreme memory option in the BIOS?
    Yeah, I set this on and off many times, I also manually set my memory to work under the specified preferences of the Memory itself thru BIOS.
    Didn't seem to change anything..

    What I also did is to elevate the Voltage on each ram chip since I've heard this could sometimes trigger the OS to recognize and use all the 16 GB.
    Did not help either.

    Its seems i did everything I possibly could but i am certain there must be a solution for it!! Since all my hardware supporting everything, it must be so tune up issue. Or maybe my windows registry somehow corrupted I don't know.
  8. Well update on my problem.

    Issue has not been resolved :/

    I tried playing around with the chips.
    I don't get what people tell me "they come in pairs" I hear that all the time..
    I got 4 chips of 4 gb each ..
    Tried switching between these not working!

    Please look at the picture I posted it might give some clues to whats going on

    I really need help!
  9. Pairs meaning a dual channel kit. So when you buy a memory kit it will come in 2 physical sticks. What I meant was to switch stick A with stick B but you already done that and it didn't help. What speed are the memory? Try manually changing it in the bios to whatever it is supposed to run at. Did you try running EACH STICK INDIVIDUALLY to make sure that all the sticks are still good and not faulty/dead?
  10. I will try doing that and update soon!
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