VRAM, which stands for video random access memory, is the dynamic random access memory used for storing image and video data for a computer. VRAM is an integrated circuit that operates as a buffer between the CPU and the computer's video card.
VRAM was developed to provide color graphics at high speeds and reduced costs, replacing earlier bitmaps as a display technology. During operation, the processor sends video data to the VRAM, which are then changed to analog signals that are sent to a display device. To avoid lag, which can lead to a flickering display, most VRAM is dual-ported so that it can both write data to the display and receive data from the processor simultaneously.
There are several different types of VRAM, from SGRAM to MDRAM. SGRAM is the least expensive and uses a single process to deliver data rather than the typical read, write and update process used by other VRAM types. RDRAM is one of the fastest VRAM types, using a simplified bus to pass data through at an accelerated rate. MDRAM is known for its efficiency because it divides the memory into 32-kilobyte chunks that can be accessed concurrently, increasing the speed of reading and writing to the VRAM chips.