8GB out of 16 after replacing the video card, what could be?

Question

linux

I changed the plug 1030 to rx580 (8gb auros).
Proc (for replacement by 2700) Ryzen 1200
Mainland gigabyte b450m ds3h
Ozu patriot 8gb (2667) x 2
Installed rx580 card, on Windows and Linux demolished nvidea drivers and installed amdshnye ones.
In bios sees all 16gb. On Windows, he writes that they say there is 16GB but uses only 8GB, cpu-z shows 16GB. In the task manager it shows that for some reason 8GB are reserved and 8 is in use. On Linux (mint 19.1) in the system information shows only 8GB. I changed it back to 1030, the visibility of the RAM in both OSes is the same as with px 580.
Dead bar? Slots on the mother?

Answer 1

Try rearranging the slats in some places, sometimes it helps

Answer 2

The question is not formulated in sufficient sequence, so I cannot give an answer to the author ... I
solved such a question on the server ... It disappeared ... Be attentive to details when acting

Answer 3

Fumble around in the bios. Update Bios and reset it.