Since only one channel works might it be good to reinstall the cpu and make sure the cooler is snug on all sides, also check for bent pins in the socket, why i want you to get it (the cpu) out in the first place.
I did it 10 times yet, and still no work. Pins are looking okay, but I don't know. The CPU made power problems too, so could it be the CPU? (When I started my PC, it just kept cutting off until I reinstalled my CPU, now PC works but RAM is a problem)
Really weird problem for me. :/
I got an old BIOS. Should I update it?
Because my case is rly bad and doesn't have holes to screw cooler up on that side, my cooler is not screwed up so as not to damage the motherboard or something like that. But it still cools the CPU fine.