a1 b1

Why does my ram only work in A1 B1 configuration but never in A3 B2 configuration, I don't change the order of the sticks and even tried to see it that'd work but no it doesn't. What's with my A2 B2 slots ? The ram just lights up and pc runs for 5 sec and then shuts down and turns back on and...

Some context here, my system has 16gb of ram which works absolutely fine and has done for over 3 years. But I realized recently that my ram was running slower than it should which I can sort in the bios simply. But reading up I noted that my ram is in the a1-b1 orientation where as Asus...