Question Dropping Ram

[NastyMonk]

Hello guys.

I have an AMD config,
Ryzen 5 1600x
AB-x370 Gaming 3 mobo
Patriot Signature 2x4GB 2133Mhz CL15

I'm getting a problem nowadays,if i open task manager, at Memory tab, Windows see 8GB RAM but I can use only 4GB.
After I restart the PC I can use all of 8GB.
I don't know why.
RAM is in dual slot.

Can somebody help me?

P.S.:Sorry my language.

 

[Lutfij]

Make and model of your PSU? Are you on the latest BIOS update for your motherboard? Mind sharing which two slots you've populated the ram on your motherboard? Which version of your OS are you on(assuming Windows 10) 1803 or 1809?

 

[NastyMonk]

My Psu is 600w , Bios wa F23, now after i read your answare i updated to F25.
Now is in #1 and #3 slot but in #2 and #4 slot steel the same error.
Windows 10 Pro 1809.