Question 2nd hand CPU mobo and ram, only one ram stick works at a time.

Jan 18, 2020
I bought a new mobo CPU and ram of my friend yesterday and have been having some trouble with the ram.

CPU: i5 8400
Ram: 2x4 T-Force Dark DDR4 3000
Mobo: Gigabyte b360m hd3
GPU: GTX 760 2gb
PSU: 750w

My PC will only boot with ram stick in, in the first channel. My mobo only has 2 dimm slots, each its own channel.

I have changed XMP in the bios from disabled to profile 1 with all default settings.

Updated bios to newest version, done a cmos battery reset.

Reseated CPU

Both of the ram sticks are functional, and I saw the PC working with a different PSU and GPU a week ago.

If I only put one stick in first channel I can fully boot into Windows and everything works fine and have tested this with both sticks, they both work fine individually.

Been testing for multiple hours, cannot find the issue please help :((