Memory not detected.

[arcoreinj]

I have a 12gb memory, 8gb DDR3 HyperX 1866mhz and a 4gb DDR3 HyperX 1866mhz.. At the BIOS the two memories were detected but it only counts the 8gb one which is on the dimm slot 1. Also when I check the This PC properties the it shows that (12gb RAM, 7.94 usable) same on the Task Manager > Performance Tab. I tried removing the 4gb memory on the dimm slot 2 and when i check the this pc properties it shows (8gb RAM 7.94 usable). I tried transferring the 8gb ram to dimm slot 2 to and still the same result (8gb RAM 7.94 usable). I tried putting the 4gb ram alone on the dimm slot 1 it shows (4gb ram 3.94) usable and when i transfer to dimm slot 2 same result. So at this point I guess there's no problem on the DIMM Slots. I also tried "Windows Memory Diagnostic" both rams were detected and no problems found. But when I check the Resource Monitor there was a 4gb + memory on the Hardware Reserved is that the problem?


Specs
APU - AMD A10-7860K
Mobo - ASUS A68-HMK
RAM -  12gb (8gb DDR3 HyperX 1866mhz and a 4gb DDR3 HyperX 1866mhz)
GPU - ASUS Strix GTX 1050ti
PSU - DeepCool DA 500M 80+ Bronze

[Guest]

When you mix DIMM sizes, the board will down size the larger stick to match the smaller one. 

 

So 12 installed but only 8 usable.

 

Find another 8gb stick and all 16gb should be available for use.

 

GL!

[arcoreinj]

But just last month It shows 12gb RAM. And now I don't know what happened.

[Guest]

21 minutes ago, arcoreinj said:

But just last month It shows 12gb RAM. And now I don't know what happened.

It's always showed 12gb. You just now noticed whats available to use. 

 

My first gen i7 system is the same way.

 

I have 2x 4gb sticks and 1 2gb stick. 

The board goes triple channel with 10gb but only 6gb available. 

[arcoreinj]

10 minutes ago, ShrimpBrime said:

It's always showed 12gb. You just now noticed whats available to use. 

 

My first gen i7 system is the same way.

 

I have 2x 4gb sticks and 1 2gb stick. 

The board goes triple channel with 10gb but only 6gb available. 

Thanks for the response..  I already fixed it.. I changed the CMOS Batt and when I booted on bios it now shows up the 12gb ram same as on windows side.

[Hairless Monkey Boy]

2 minutes ago, arcoreinj said:

Thanks for the response..  I already fixed it.. I changed the CMOS Batt and when I booted on bios it now shows up the 12gb ram same as on windows side.

Yes, I see this problem regularly, and the fix tends to be to add/remove/swap around the RAM sticks a bit and to reset CMOS, which is exactly what you ended up doing.