Resolution and number of colors are determined by the amount of video memory, and refresh rate is determined by the quality of the components. All these items need to be explained in detail. Display adapters are characterized by Resolution Color Depth Refresh Rate Bus interface Accelerator .
Resolution refers to the number of dots on the screen.
A computer display is essentially a high resolution TV set. In current use, these colors are controlled by three wires in the display cable. Each has a variable amount of voltage represented by a number from 0 to 255. This produces a theoretical 16 million possible colors. The original VGA display had a resolution of 640x480 and supported 4 bit color.