Hi there i have a issue i recently just purchased brand new case the Cooler Master CMP-500, as-well as new GPU Radeon RX 570, my cpu is a intel- i7 3700, i have 16gb of ram 4x4 not sure what the mother board is but when i tried to place my GPU inside the PCIE16X slot it does not fit, so i need to buy a motherboard any cheap suggestions i would like to spend no more then $100 AUD, thanks