The first decision you need to make is whether you need a graphics card for handling 3D images or whether you are simply requiring 2D image rendering. For 2D requirements, you need only a low-cost solution. In many cases, an integrated graphics solution will suffice for 2D applications.
However with 3D graphics, the performance of the graphics card will impact directly on the frame rate and image quality of 3D programs and games. The differences between the low and high-end cards can be substantial, both in cost and performance.
Rendering 3D graphics is like lighting a stage, both the geometry of the shapes in question and the lighting of it need to be taken into account. The geometry of an image calculates the parts of an object that can and can't be seen, the position of the eye and its perspective. The lighting is a calculation of the direction of the light sources, their intensities and the respective shadows that occur. The second part to presenting a 3D image is the rendering of colours and textures to the surfaces of the objects, and modifying them according to light and other factors.
Most modern graphics cards include a small microchip called the Graphics Processing Unit (GPU), which are provide the algorithms and memory to process complex images. They reduce the workload of the main CPU, and provide faster processing. Different graphics rtx 3090 cards have different capabilities in terms of processing power. They can render and refresh images up to 60 or more times per second, calculate shadows quickly, create image depth by rendering distant objects at low resolution, modify surface textures fluidly and eliminate pixelation.