16gbs but only 6.88gbs are usable?

[torei.n]

My build consists of:
Motherboard:ASRock A320M-HDV
CPU: Ryzen 3 2200G
GPU: EVGA GTX1050ti 4gb
HDD: Hitachi 3TB
RAM: 1x8gb DDR4 Corsair Vengence 2400Mhz/1x8gbs DDR4 Team Vulcan 2400Mhz
No SSD
PS: 450Watt +80 Insignia

Before i had 16gbs of ram, i had 8gbs. And when i had 8gbs only 6.88gbs were usable. But when i upgraded to 16gbs of ram, it still tells me that only 6.88gbs are usable. I dont know how to fix this.

 

[camieabz]

First up try both 8GB stick individually in the original working slot to ensure both work (6.88GB or whatever - as long as they work).

Assuming both work, ensure that dual channel RAM in BIOS is set, and disable any onboard video options in BIOS, and double check that monitor is plugged into gfx card video output, and not motherboard video output.