RAM issue and ASUS motherboards

I RMAed my faulty ASUS motherboard and it still threw a ram error. I pluged the ram in to slots B1 and B2 and it worked. I could send it back and get a different board with four functioning slots but forget it. I'll deal. This is the final straw with ASUS however. 3 boards with faulty slots and the first bad board popped up over 1.5 years ago. They clearly have some serious manufacturing problems that they refuse to address. Shame.