Video Random Access Memory (VRAM)
Definition - What does Video Random Access Memory (VRAM) mean?
Video random access memory (VRAM or video RAM) is a high-speed array of dynamic random access memory (DRAM) used to store the image and video data that a computer displays. VRAM is an integrated circuit that serves as a buffer between the CPU and video card. VRAM was originally designed as a high-resolution graphics adapter. The higher the video memory, the higher the capability of the system to handle more complex graphics at a faster pace.
VRAM is also known as a frame buffer or simply video memory.
Techopedia explains Video Random Access Memory (VRAM)
VRAM was created in 1980 and commercially introduced by IBM's R. Matick and F. Dill in 1986. Designed to provide high-speed color graphics at reduced costs, VRAM surpassed earlier display screens that included large workstations and limited bitmaps.
When an image is to be shown on the display screen, the processor reads it first and then it is written to the VRAM. This data is then changed by a RAM digital-to-analog converter (RAMDAC) to analog signals, which are then sent to the display screen. All these processes occur so quickly that the users cannot perceive them. VRAM chips are usually dual-ported, meaning that when the display reads from the VRAM for refreshing the presently displayed image, the processor writes a new image to the VRAM simultaneously. This helps to prevent the display from flickering.
Types of VRAM include:
- SGRAM: Clock-synchronized and the least expensive type of memory. Data may be modified in a single process instead of the typical order of read, write and update.
- RDRAM: One of the fastest video RAM technologies with a data transfer rate (DTR) up to 800 MHz. Allows data to pass through a simplified bus. May have dual channels, which doubles the transfer rate,
- Window RAM (WRAM): High-performance and dual-ported VRAM with approximately 25 percent greater bandwidth than regular VRAM.
- Multibank Dynamic RAM (MDRAM): A highly efficient RAM that helps to divide the memory into several 32 KB parts, which may be accessed separately. Concurrent access of the memory increases overall performance. MDRAM is less expensive than most VRAM.