If the USB slots on the back of the motherboard don’t support USB 2.0, can you use USB 2.0 by installing a PCI card with USB 2.0 slots? Or will it be impossible to use USB 2.0 on a motherboard like this?
Hi and Welcome!
that’s why USB 2.0 cards are available
Please note, that a PCI card will only reach about 16 MBytes/sec (compared to good integrated USB controllers that reach about 30 MBytes/sec).
I strongly recommend cards with NEC chipset which are the most compatible ones. And stick with the USB2.0 drivers provided by the operating system instead of installing drivers from the manufacturer.