I have DDR3 motherboard if I will use DDR5 graphic card with it it will work or not

Solution
Graphic card memory is independent from system motherboard memory and no incompatibility would arise from it. They perform in independent manner with different hardware layers in between that ensure compatibility of graphic card with motherboards regardless of the type of memory used either on the graphic card or the motherboard.

R0GG

Distinguished
Graphic card memory is independent from system motherboard memory and no incompatibility would arise from it. They perform in independent manner with different hardware layers in between that ensure compatibility of graphic card with motherboards regardless of the type of memory used either on the graphic card or the motherboard.
 
Solution
that your video card has GDDR5 (Graphic Double Density Ram) has no direct link with the type of DRAM (computer Double Random Access Memory) is used with your computer, now that said, a video card is directly dependent on the type pcie slot your motherboard has to power/utilize it as well as the size of your PSu to be able to power that video card with your motherboard.

so I would ask what make and model are your motherboard , power supply and video card your trying to install ?