BIOS detects RAM but Windows does not - Asus Z170 Pro Gaming

[Nap5t3R]

Hi all,

Firstly, I am not quite familiar with the RAM latency, voltage, dual channel etc. So please bear with me if enough information is not provided.

I recently upgraded my system as below:

Old spec:
MOBO - Asus Z170 Pro Gaming
Processor - i3 6100
RAM - 2x4GB Corsair (i think 2400Mhz, Motherboard says so) - 1 in slot #2 and 1 in slot #4

New spec:
MOBO - same, but update BIOS to be able to use Kaby Lake processor
Processor - i7 7700
RAM - 2x4GB Corsair (in slots #1 & #2) 2400Mhz
2x8GB Corsair (in slots #3 & 4) 3000Mhz

I understand the upgrade would make the RAMs effectively work at 2400Mhz. But beyond that I am facing an issue were Windows is detecting only 12 GB of RAM (1x4GB + 1x8GB) and not the other 2. Even the Task Manager's Performance tab shows only 2 slots used out of 4.

Link to the Screenshots of CPU-Z and Windows : https://imgur.com/a/n9phfn5

However, BIOS and CPU-Z show all 4 RAMs. Could someone please shine some light on the issue and what can be done to correct it?

 

[Lutfij]

Why are you mixing and matching sticks of ram? I'm a strong advocate of not doing so. It only adds more to the issue/stress when you just be done with a ram kit.

In your scenario, you should choose the higher capacity ram kit and populate them in the slots stated in your manual. You should be moving forward. If the 16GB DDR4-3000MHz ram kit doesn't work, you may want to backup your critical content and reinstall your OS after creating a bootable installer using Windwos Media Creation Tools.

 

[Tsawind]

You have the matched sticks in the proper slots on the mother board I hope?? Not sure if this helps, but it *could* cause that issue.

 

[LaFaye_58]

first let me give you to things...Motherboard Manual- https://cdn.billiger.com/dynimg/VCAh4KJmY4YCONFl0-bTQXt4H9rycHjeBa9LTdXG2DAf8amwnsOLSjAO7I5RvkRNl4unjdCrum6l8cHAyF09FA/Asus-Z170-PRO-GAMING-90MB0MD0-M0EAY0-Bedienungsanleitung-637b36.pdf

second a message from ASUS about you memory -https://www.asus.com/us/Motherboards/Z170-PRO-GAMING/specifications/

now even though both might be the same information. the one from asus is for now the other is for download for later to keep at all times.
if you ram is not being recognized there are 4 possible problems. 1. not plugged in properly 2. damaged ram . 3. wrong types( motherboard cant handle them) 4. not in sync slots ( 2400. in slot with 2400 right beside it .and 3000 side by side too.) or you motherboard has a slot problem but on #4 you seem to have them in properly..you need to check 1,2, &3 plus your motherboard. (for motherboard testing unless your a tester you'll need testing tools for that, I recommend a compute technician.