Ram in A2+B1 equals D. Dual Channel
Ram in A2+B1 equals D. Dual Channel
Your motherboard has some defective slots, but the middle ones are functional. Using slots A2 and B1 together should work, though it may not be dual channel. Check your specific model for compatibility details.
Your system uses slots A2 and B1, but it won't work in dual channel mode. Are you sure your motherboard is still covered by the warranty?
No guarantee with this Asus Z370-F, bought used for 40 Euros—it was a smart price. No dual channel support. I’m curious since they say A and B are channels but you need matching letters to work; combining A2 with B1 sounds completely out of the way online.
The concern about A2+B1 not being dual channel comes from shared pins between A1/A2 and B1/B2. While placing memory close together improves stability, it isn't strictly necessary.