Etheruem classic will have a higher hash rate and any motherboard is suitable for mining. If you have 5 or more video cards, then you need to buy special motherboards and an expensive multi-core processor so that the PСI-e port speeds are 8x 8x 8x 8x 8x for Ethereum mining.
I'm too lazy to do this for one farm, so I mine Ravencoin (RVN) or etheruem classic