F3-14900CL9-4GBSR - Gigabyte 970A-D3P (rev 2) - AMD FX-6100 - half memory available

[vadimtk]

Hi I have configuration above.

In BIOS I see 8GB of memory,
but memtest86 shows only half of that, and Windows 7 / 10 64bit
shows 3.97GB memory available.

Where do I start to debug this?

[GSKILL TECH]

Try each stick to see if each shows up 4GB.

Have you tried slots A1 A2? A2 B2?

[vadimtk]

it won't start with only one slot

[GSKILL TECH]

You tried every slot?