[SOLVED] Why does my computer keep changing the amount of ram it has

[Vageta35]

Yesterday I checked my computers ram and it said there was 7.93/16 gb of ram usable and I thought it was weird that it said I have 16 gb of ram even though I really have 12 gb (1x8gb and 1x4gb) i opened my computer and cleaned the ram sticks and put them in and it said I had 12 gb of ram (which I do) and I turned it off overnight and turned it on in the morning and now it says 7.93/16 gb of ram usable again

my specs are
Micron 8192mb 2133mhz
Corsair 4096mb 2133mhz
Prime b350 plus motherboard (bios ver 0805
Ryzen 3 1300x
Gtx 1060 3gb

 

[Ralston18]

How did you check the RAM?

Has the problem always existed or did the problem just start?

Appears to me that the 4 GB module is "appearing/disappearing".

What are the detailed specs for both RAM modules?

Check the motherboard's supported RAM via the manufacturer's QVL (Qualified Vendors List).

I found the following link (do verify that the link is a correct match for your motherboard):

https://dlcdnets.asus.com/pub/ASUS/...E13723_PRIME_B350-PLUS_UM_V3_WEB_20171114.pdf

Physically numbered Page vi and Section 1-4 (Page 1-12) provide memory information and supported configurations.

Double check the RAM and configuration.

Any performance changes if you uninstall the 4 GB module?