Motherboards usually have horribly placed PCI-E slots. Normaly a single card very often takes 2 slots and it is not possible to use all empty slots.
Thanks to Riser Card Extender Ribbon Cable You can connect any card, because this way it is possible to provide sufficient airflow and space for mounting card.
Riser is built of female PCI-E 16X socket at one end, flat cable and male PCI-E 1X plug at another end.
It is the cheapest, effective solution for better cooling and allows to use all PCI-E 1X slots available on a board.