$ 200 for a motherboard with 8 graphics cards?
+ you still need to buy a processor, cooler and RAM
It is very expensive, I buy ready-made kits no more than $ 100 (motherboard, processor + CO and memory).
Maybe I don't understand something about mining, but I always try to reduce the cost of those components that do not affect performance.
If we save on raising, we will spend on additional cooling