[SOLVED] Although I have installed 16gb of RAM on my PC, only 7.95 are "usable"

[SaltJackalope]

I originally had 8gb of DDR4 RAM (2x4), but recently purchased an additional 8gb (2x4). I can run my computer using exclusively my new RAM or exclusively my older RAM; however, only half of my RAM is usable while using all 4 slots. Both sets of RAM are from the same company, but one pair is 1200mhZ and the other is 1066mhZ. I don't think this should render one of the sets of RAM as useless... any help would be greatly appreciated!

 

[SaltJackalope]

Here are my specs btw:

Operating System
Windows 10 Home 64-bit
CPU
AMD Ryzen 5 1500X
14nm Technology
RAM
16.0GB Dual-Channel Unknown @ 1066MHz (15-15-15-36)
Motherboard
Gigabyte Technology Co. Ltd. X470 AORUS ULTRA GAMING-CF (AM4)
Graphics
AAA (1440x900@60Hz)
3071MB NVIDIA GeForce GTX 1060 3GB (Gigabyte)
Storage
931GB Western Digital WDC WD10EZRZ-00HTKB0 (SATA )
223GB ADATA SU635 (SATA (SSD))

 

[Calvin7]

Adding extra memory to existing memory has no guarantee to be compatible with your existing memory. It is possible that using exact match, same thing, identical modules may raise your chances of the memory working together over random modules.

The results you have are typical of using multiple kits of memory. Since you can make any combinations you want, you are free to do your own compatibility testing with no guarantees.

Since combining memory that has never been tested together before for do-it-yourself compatibility testing can be expensive, it is not something that is not recommended.

 

[SaltJackalope]

It turns out that when I take out my new memory and only use the original 2x4 ddr4 RAM, it does the same thing and says "4.1GB hardware reserved"... so I don't think that it is due to incompatible RAM.

 

[Permanent]

No joke, registered today because I've had the same issue for a few weeks when I installed new RAM sticks. So glad it's not just me.

@SaltJackalope, try running CPU-Z. I ran it, and it detected my 24GB, compared to Windows which only detects 16GB (see image below) - from what I believe, if it shows on CPU-Z then it shouldn't be due to incompatible RAM.

 

[SaltJackalope]

I just tried that and CPU-Z does recognize my 16GB of DDR4 RAM

 

[Permanent]

I just tried that and CPU-Z does recognize my 16GB of DDR4 RAM

I just updated my BIOS, and my final stick of RAM has been miraculously been recognised! Try that

 

[SaltJackalope]

Okay, I just updated the bios, and now it shows that I have 7.95gb of ram and doesn't even say that the other 8.05 is hardware reserved

 

[Permanent]

Do they all have the same statistics? You said your RAM was 'Unknown', go back to CPU-Z and check under the SPD section - that should give you some further details.

 

[SaltJackalope]

I fixed the problem! Basically, I determined that some of my RAM slots were detecting the RAM but not using it, which meant it was most likely a CPU problem. I checked my CPU for any bent pins or debris and reinstalled it. Now all 16gb of ram are being used. Hopefully this thread helps anyone with the same problem.