Dual RAM not working ASRock Z370 - faulty mobo?

[teepweep]

Hi all,

I finally upgraded my PC (8700k) but I'm unable to get dual RAM working in slots A2/B2 (the preferred slots). The PC does not post, I just have a black screen.

If I put both sticks of RAM in B1 and B2 they work fine, but it's not dual mode. If I try 1 stick in A1 or A2 only, the PC does not boot, so the A-channels don't seem to work at all.

Things I have tried:

Tried a different 8700k CPU, no difference
Tried different sticks of corsair 2x16GB RAM, no difference (CMK32GX4M2D3200C16 / CMD32GX4M2C3200C16)
Reseated the CPU and eased pressure of the 212 evo cooler, no difference
Tried XMP on and off, no difference
Checked for bent pins, none at all

Does anyone have any ideas? Does the fact that none of the A-channels work with single memory sticks indicate a faulty board?

If I use both B1 and B2 channels my PC still runs great and flawlessly, it's super fast. But I want the dual support obviously

Thanks!

 

[drkatz42]

tried slots a1/b1 ?

 

[teepweep]

I can't even put a RAM stick in A1 actually, because the Hyper 212 evo fan is in the way! But A2 definitely does not work with a single stick.

Edit: Swapped cooler fan around, A1 definitely isn't working solo or dual. PC doesn't boot.

 

[Guest]

If you are still having this problem, try the latest version of Memtest86 to test the memory in slots A1 or A2. Make sure the version of Memtest86 you use supports Coffee Lake CPUs.