Certain video card models by Nvidia and AMD use a type of video memory called GDDR5, which stands for Graphics Double Data Rate 5. The memory bandwidth of GDDR5 VRAM differs from each video card model. If you know the memory clock frequency and memory interface width of a video card's GDDR5 VRAM, you can calculate its memory bandwidth immediately.
Divide the memory interface width of the GDDR5 VRAM by eight.
Multiply the answer with the memory clock frequency (in MHz) of the GDDR5 VRAM.
Multiply the answer by two and then divide it by 1000 to get the memory bandwidth of the GDDR5 VRAM in gigabits.