We can see that the above car model is designed using square planes, and there are so many vertices, now if we want to move this car in our game then each and every vertex’s positional matrix must be multiplied with 3D translation matrix.
Now a car is just one model in the game there are many other models like surroundings e.g. streets, mountains, trees, roads, etc. and these will also have many vertices.
As the car moves there will be change in surrounding so we have to perform transformation matrix all the time on all the objects in the scene.
This is where things get difficult for the CPU, because the CPU is designed for serial processing and performing matrix calculation continuously needs parallel processing.
Here is when GPU comes into the scene with its parallel processing and many ALUs it can handle continuous matrix calculation and also other aspects like FPS, Ray tracing, etc.