Need to check my memory controller on Ryzen 5 2600 cpu. The ram sticks is ok but my system only detects 50% of the usable memory. BIOS detects 8GB + 8GB but only count 8GB as usable and not 16GB. BIOS is reset and updated. I'm absolutely sure that the memories working correctly to 100%.
In Win 10 pro 64-bit there is 16GB and only 8GB detected as usable memory.
This type of problem is rather difficult to troubleshoot since it can be either software or hardware issues.
1) One issue that can cause your RAM Memory not showing up completely is if the RAM MEMORY is not 100% compatible with the Motherboard or CPU. Is your RAM Memory listed in the Motherboard's QVL List? Ryzen CPU are very sensitive to the type of RAM Memory installed. That is why is always best to purchase RAM modules from the QVL list that has been tested by the manufacturer to be 100% compatible with Ryzen and the Motherboard.
2) I would run MEMTEST86 just to verify all your RAM Memory modules are good and not defective. At least 2-3 passes with NO ERRORS.
3) Make sure you have the latest BIOS and CHIPSET installed. Especially the BIOS. An older BIOS Version may not show the entire amount of RAM installed.
4) Does BIOS show the Full amount of RAM installed correctly?
5) Have you tried to "Enable" the memory in Windows us MSCONFIG.exe?
6) Does Task Manager show 8 gigabytes of 16 gigabytes of RAM as "Reserved"?