VRAM

Video Random Access Memory chips that determine the performance capacity of video adapter hardware in computers. In particular, they allow for reading and writing of graphics images to take place simultaneously. At the time of this writing, authors of hypermedia are advised to purchase a computer with at least 2Mb of VRAM. (See also RAM )

Short for video RAM, and pronounced vee-ram. VRAM is special-purpose memory used by video adapters. Unlike conventional RAM, VRAM can be accessed by two different devices simultaneously. This enables the RAMDAC to access the VRAM for screen updates at the same time that the video processor provides new data. VRAM yields better graphics performance but is more expensive than normal RAM. A special type of VRAM, called Windows RAM (WRAM), yields even better performance than conventional VRAM.

Stands for "Video Random Access Memory" and is pronounced "V-RAM", not "Vram". Plain old RAM is great for loading and running programs, but when you need graphics power, VRAM is where it's at. VRAM, or video random access memory, is the stuff used to store image data for the computer's display. It acts as a buffer between the CPU and the display -- when a picture is to be displayed, the image is first read by the processor as data from the main memory and then written to the VRAM. The data is then converted by a RAM digital-to-analog converter (RAMDAC) into analog signals that are sent to the display. Of course, no normal person ever notices this, since it happens so quickly. Unlike most normal RAM, VRAM chips are dual-ported, which means that while the display is reading from VRAM to refresh the currently displayed image, the processor is writing a new image to the VRAM. This prevents the display from flickering between image redraws. In case you're not confused enough already, there are many different types of VRAM. One popular kind is called Synchronous Graphics RAM (SGRAM). It is an inexpensive type of RAM that is clock-synchronized. This means it allows data to be modified in a single operation rather than as a sequence of read, write, and update operations. It also allows background, foreground, and image fills to be handled more efficiently. Another type of VRAM is Rambus Dynamic RAM (RDRAM). It is designed by Rambus and includes a proprietary Rambus bus that speeds up the transfer of data through it. Video editing pros like this chip since it is optimized for video streaming. A third type of VRAM is Window RAM (WRAM). This is very high-performance kind of VRAM that is dual-ported, has about 25% more bandwidth than standard VRAM, yet costs less. Finally, there is Multibank Dynamic RAM (MDRAM). This is also a high-performance RAM, developed by MoSys, that divides the memory into divisions of 32 KB, which can be accessed individually. This makes memory transfers more efficient and increases overall performance. Another advantage of MDRAM is that it can be manufactured with just the right amount of RAM for a given resolution, so it is cheaper to manufacture than most other types of VRAM.