Besides, can I use a ddr5 graphics card on ddr3?
There is no such rule that you should use specified graphics card for ddr3 motherboard. You can use any of the ddr4 or ddr5 graphic cards in your PC. But keep in mind that the CPU doesn't become a bottleneck. You need a good CPU for a good graphics card or you won't get desired performance.
Additionally, does it matter what DDR my GPU is? Distinguished. Your motherboard memory and your graphics card memory can be different DDR types. In fact, the graphics card won't use the the motherboard DDR memory even if both are the same type. They don't and shouldn't interfere with each other.
Correspondingly, how do I know if my motherboard supports ddr5 graphics card?
DDR5 memory is for a graphic card and the interface for a graphic card is generally pci-express slot (pcie) and a quick google of the motherboard shows it has a single pci express card. Yes it will work, just put the graphic card into the slot it fits into and plug in the power in the back of the card.
What does ddr5 mean on a graphics card?
Graphics Double Data Rate 5
