RAM errors only when using 2 sticks; what does it mean?

[Sin Stalker]

So I've had instability for awhile now and it has slowly been getting worse. I've updated BIOS, replaced the CPU and been doing nothing but troubleshooting.

 

I have 4 dim slots on my asus b350-f motherboard.

 

When I run an AIDA64 stress test on cache, I get hardware errors but only when I use 2 sticks of ram or the 1 stick is in the A1 or A2 dim slots.

Even if I put both RAM sticks in B1 and B2 (not in dual channel then), then I'll get the error. If I put both in A1 and B1, or A2 and B2, I get errors.

 

If I put 1 stick in B1 or B2, I don't get any errors. If I put 1 stick in A1 or A2, I get errors.

 

Is the RAM bad or is the motherboard bad?

[SpiralTTGL]

if it works in other slots then its the motherboards slots

[Kushagra_kj10]

Check the motherboard just over the ram slots it should clearly say where to insert the ram sticks for optimal performance. 

[Sin Stalker]

42 minutes ago, Kushagra_kj10 said:

Check the motherboard just over the ram slots it should clearly say where to insert the ram sticks for optimal performance. 

I have and did. I listed all configurations in my OP.