I have 16GB of RAM that is installed in my system but only 7.95GB is usable.

[n1tRo]

Problem:
I have installed 16 GB of ram in my system but when i check in the system status or properties it shows 16 GB (7.95 usable)

I just completely dismantled my pc and cleaned it but after turning it on i noticed this issue in the system properties that 16 GB (7.95 usable)
But before cleaning I had the same configuration or system specs and i didn't faced any issue. I was able to use full 16 GB of ram.

I have tried several methods like:

1. Changing registry in memory management from zero to one
2. I have tried the virtual memory setting paging to no paging file
3. I have also untick maximum memory in the msconfig
4. I have also check both of the rams one by one.
   First i used only crosair in the a2 slot on the motherboard and check the system properties it should just as 8GB then i checked for the gskill and it showed same in system properties as 8 GB. (I guess their is nothing wrong with the RAM sticks)
5. I have also tried the a1 and b1 slots on the motherboard but when i did it my pc showed an error. But it still booted into windows but still the problem was not fixed. It still showed 16 GB (7.95 usable) message.

My system specs:
PROCESSOR : AMD RYZEN 5 2600
MOTHERBOARD : MSI B450 GAMING PLUS MAX
POWER SUPPLY : COOLERMASTER VS 550 Watt
RAM : 8 GB x 2 (3000MHz)
GRAPHICS CARD : GALAX 1CLICK RTX 3060
CABINET : CIRCLE ELIMINATOR X1 RED
LED

RAM: I have 2 x 8 GB of RAM. 1st one is CROSAIR Vengence 3000 mhz and 2nd one is GSKILL RIPJAWS 3000mhz
Crosair ram is installed in A2 slot on the motherboard and Gskill's ram is installed in B2 slot of the motherboard.

I have provided some screenshots of the ram usage in game (Counter Strike Global Offensive)
And some screenshots of the problem

BIOS: In BIOS it shows only 8 Gb of RAM but when i check in detail it detects both the RAM. (I have provided photo of it).

 

[Dg834man]

Check the cpu for bend pins, you tried a single stick in b1/b2 to verify the channel is working

 

[Grim5]

One stick could be faulty, try different slots, one stick at a time etc

 

[Tetras]

Did you reseat the cooler when you cleaned it? You could try loosening the screws slightly as overtightening / overfitting a cooler can cause memory issues with ryzen.

 

[arknor]

is the rest showing as hardware reserved in task manager? theres a probably setting in the bios for reserving memory for GPUs, I think it's usually only for onboard GPU though

 

[Joxeon]

Try swapping the sticks around.

 

[JasonM]

My first thoughts is it's either dirt/grease on the gold memory contacts, or ESD damage to a memory chip when it was dismantled.

I would spray the gold memory contacts down with electronic cleaner, then re-install the memory again.