I wouldn't think a standard ATX motherboard would fit in a BTX case, as it would entirely defeat the purpose anyway. BTX repositions things on the motherboard to theoreticly improve airflow to the places needed most. I wouldn't bother getting anything BTX any time soon, as there is not real reason to. It's an attempt at helping to keep the power hungry prescott oven running a bit cooler. Not that it isn't taking every thing I dish out to it, but it does run a tad warm for my tastes.