Only 4GB usable of 16GB on Windows 10 64-bit

Hi Elindwel,

Thank you for posting your query in Microsoft Community. I regret the inconvenience caused to you. Let me help you.

I suggest you to run Memory Diagnostic Tool.

Steps to Run Memory Diagnostic Tool:

1.      Type Memory Diagnostic Tool in search box.

2.      You will get a pop up, just click on Restart now and check for problems.

It might take several minutes for the tool to finish checking your computer's memory. Once the test is completed, Windows will restart automatically.

Reference, http://social.technet.microsoft.com/wiki/contents/articles/29343.running-windows-memory-diagnostics-tool-in-windows-10-technical-preview.aspx

I hope the issue will be resolved. Reply with the details and updated status of the issue. We will be happy to assist you further.

Are you running the 64-bit version of Windows?  If not, there's your answer.  If you do have the 64-bit version, press the Windows key + r, and type msconfig in the run box and hit enter.   In the Msconfig window, click on the Boot tab, and then on Advanced Options.  If the Maximum memory box is checked, uncheck it then close the Msconfig window and reboot.

It is 64-bit, in addition I had already run this but did it again, and did it Extensive 2 passes with cache and now have two entries in System Log that Say "The Windows Memory Diagnostic tested the computer's memory and detected no errors" it passed all tests.

I have memory check off, have tried it both ways on the Boot Advanced Options (16GB checked and unchecked).

Other ideas?

Shawn

It is 64-bit, in addition I had already run this but did it again, and did it Extensive 2 passes with cache and now have two entries in System Log that Say "The Windows Memory Diagnostic tested the computer's memory and detected no errors" it passed all tests.

I have memory check off, have tried it both ways on the Boot Advanced Options (16GB checked and unchecked).
Other ideas?

Shawn

The problem could be the mainboard. check in your Bios you have set dual channel

I solved this problem yesterday. Maybe is an old issue to you, but someone else look at this post maybe will find helpful this information.

My Bios was telling me that my mainboard was settled in a single channel instead of a dual channel(RAM). It means that my mainboard will allow to use just 1 RAM  instead of the 2 RAM. I have two memories RAM of 4Gb each, and windows was using just one because of this issue. Windows system said i have less than 4Gb usable the others 4 Gb was reserved.

So the problem was the mainboard. My mainboard is an "ASROCK 970 EXTREME4" and it is suppose to automatically switch from single to dual channel when detect two or four memories in the slots. The RAM has to have the same characteristics. ((the same brand, speed, size and chip-type). and if there are just two rams have to be in the same slots color (blue is the best place in this instance), That's my mainboard you will have to check yours :P

I have the same everything. So, my last chance was to take away the rams and the video cards, Clean them up, and put it again. After that I got activate the dual channel in the bios. Then, I went to windows and do the process on the system configuration.

Process of system configuration:
1) open system configuration
2) Boot
3) Advanced options
4) Unmark maximum memory
5) Ok
6) Apply
7) Ok
8) Restart PC

There are a lot of videos of this "system configuration process" on youtube, and JimWynne already has post it.

I attach a picture of the bios saying dual channel you can get the idea where to find it (most likely you have other Bios)

I hope this helps :)