Is it possible to use GDDR5 graphic card with DDR3 or DDR4 motherboard RAM?
Yes, it is possible, because the graphics card works independently and have its VRAM. Therefore, the type of motherboard RAM is not important while selecting the graphics card.
The thing you must consider is the type of slot your computer has, it may be PCI-E x16 or PCI-E2.0 or latest versions. Graphics card must be compatible with the type of slot to operate.