Video memory is RAM memory that has been installed on a video adapter. RAM memory is Random Access Memory and is a volatile form of memory. Video memory first places an image in the sequence it may be running into a frame buffer, which is a form of bitmap. The image is then shown on the screen as we see it either in picture form or film form.



The amount of video memory available on the video adapter is an important factor to how the image is viewed by the user. This is what determines the maximum resolution and color depth of the film. Once this is known, it is easy to see how video cards have evolved from the simple colors into an array of available colors in varying resolution. If the amount of video memory stored on the video adapter is small, then the resolution and color depth of the resulting image will be low upon viewing. If high resolution is desired by the person using video memory, then a higher amount of video memory is needed on the video adapter.

There are a few types of video memory. Just as RAM has varying forms of memory, so does video memory. Some of the more common types include VRAM (Video Random Access Memory), WRAM (Windows Random Access Memory), RDRAM (Rambus Dynamic Random Access Memory), and SGRAM (Synchronous Graphic Random Access Memory).

Windows Random Access Memory supports two ports that enable it to retrieve memory at the same time that it is receiving memory. This makes it faster than VRAM and comes with a lesser price tag. Most of the cost difference comes in the fact that WRAM supports large blocks or windows of video data.

Rambus Dynamic Random Access Memory has a transfer rate of up to 800 MHz. This is faster than the average SDRAM. For this reason, RDRAM began replacing VRAM in many products in 1997. This type of video memory is often found in the Pentium processors in computers.

Synchronous Graphic Random Access Memory is used in graphic accelerators. It can synchronize with the CPU bus clocks up to 100 MHz using one port with the ability to open two memory pages simultaneously. It also uses other techniques to increase bandwidth for images.

With video memory your needs depend upon the amount you use the graphic accelerators and video adapters. For those with low usage, VRAM may be all that is necessary to achieve desired results. Graphic artists will most likely be concerned with the amount of bandwidth as well as speed, choosing to use SGRAM and RDRAM video memory types as a solution. Requirements to get a job done will have an impact on the choices made and the cost involved in investing in such additional memory types. Upgrading is an option for those seeking more speed and bandwidth and can be achieved by simply changing the graphic accelerator and video adapter cards in the CPU. Switching to a more powerful processor may also be needed if upgrading for optimum performance in video memory.