Q. Describe the Graphic Accelerators?

A Graphic Accelerator is actually a chip as a matter of fact most significant chip in your video card. The Graphic Accelerator is essentially the modern development of a much older technology known as the Graphic Co-Processor. Accelerator chip is in fact a chip that has built-in video functions. These functions execute algorithms for image rendering and construction. It does a lot of work that would otherwise have to be done by microprocessor.  Hence accelerator chip is actually optional however very important for good graphics performance. 

The graphic accelerator concludes whether your system can show 3-D graphics, how quickly your system displays a drop-down menu and how good is your video playback etc. It determines the amount as well as kind of memory in framebuffer and also the resolution your PC can display.

The first major graphic accelerators were made by S3 Corporation. Modern Graphic accelerators have internal registers as a minimum 64-bit wide to work on at least 2 pixels at a time.  They can employ the standard Dynamic RAM (DRAM) or more expensive however faster dual-ported Video RAM (VRAM). They support at least the standard resolutions up to 1024×768 pixels. They frequently use RAMDACs for colour support providing full 24-bit or 32-bit colour support.  A RAMDAC (Random AccessMemory Digital-to-Analog Converter) is a microchip which converts digital image data into analog data required by a computer display. Though the higher the resolution needed, the higher is the speed at which chip has to function. So for a resolution of 1280×1024 the chip operates at 100 MHz  At the cutting edge of technology chips now run even as fast as 180 or 200 Mhz.