The video memory is such an important component of the video card, and indirectly the entire PC, that several new memory technologies have been created specifically for it to improve the speed with which information can be pumped into and out of the video memory. Take a look at the various memory technologies now being used.

Standard (Fast Page Mode) DRAM : The oldest technology used in video card memory, fast page mode (FPM) memory is now considered "standard" DRAM as it has the fewest performance-enhancing capabilities of the different types of memory on the market. FPM DRAM is a technology used primarily for main system memories (even there, it is now considered a poor performer) and is not really well-suited for high-performance video applications. FPM is the least expensive type of memory available for video, and is used today mostly on low-end or generic cards (as well as older cards of course). For many applications they can be quite satisfactory; however, they reach their limits quickly when trying to use high resolution modes, especially in true color. The limitations of standard DRAM are due to two primary effects: it is single ported (which means it can only do one access at a time) and it runs at a relatively low speed and access width. Newer technologies improve performance by dual porting the memory (VRAM), increasing the bandwidth of the memory (SGRAM, MDRAM) or both (WRAM).

Extended Data Out (EDO) DRAM : EDO DRAM is the same as standard FPM DRAM except for a slight modification in the access cycle that gives it a small performance boost. With EDO DRAM, one read to memory can begin before the last one has completely finished; this yields a raw speed improvement of between 5 and 20 percent, depending on whom you ask. Originally used only for main system memory, EDO DRAM is becoming more popular on video cards because it provides slightly improved performance over standard DRAM at the same cost. (At one time EDO was more expensive than FPM but due to supply and demand effects now, EDO is actually the same cost or lower).

Video RAM (VRAM) The traditional, standard DRAM used for video cards typically does not have enough bandwidth to handle the demands of running a card at high resolution and color depths, with acceptable refresh rates because of the two competing access factors -the processor writing new information to the memory, and the RAMDAC reading it many times per second in order to send video signals to the monitor. To address this fundamental limitation, a new type of memory was created called video RAM or VRAM specifically tailored for use in video systems. The difference between VRAM and DRAM is that VRAM is dual-ported. This means that it has two access paths, and can be written to and read from simultaneously. Dual-porting allows operations to occur without bumping into each other. Don't confuse VRAM with the generic term "video RAM" or "video memory", which just refer to the memory in the video subsystem in general. VRAM provides substantially more bandwidth than either standard DRAM or EDO DRAM. It is more suited for use in systems requiring high resolution and color depth displays.

Window RAM (WRAM) Window RAM or WRAM is a modification of regular VRAM that both improves performance and reduces cost on a bit-for-bit basis. WRAM is also dual-ported & has about 25% more bandwidth than VRAM, incorporating additional features to allow for higher performance memory transfers for commonly used graphical operations such as text drawing and block fills. WRAM is less expensive than VRAM to manufacture (although still more expensive than DRAM). WRAM is suitable for use in high-end graphics cards and was first made popular by Matrox's Millenium series. A card with WRAM and a RAMDAC fast enough can handle even very high resolutions (1600x1200) at true color. Note: Window RAM has nothing to do with Microsoft Windows.

Synchronous Graphics RAM (SGRAM) A relatively newer RAM technology, Synchronous Graphics RAM or SGRAM tackles the poor performance of regular DRAM by increasing greatly the speed at which memory transfers take place. SGRAM also incorporates specific performance-enhancing features designed to work with acceleration features built into video cards, to greatly improve overall video processing speed. SGRAM is still single-ported, unlike VRAM or WRAM, but offers performance that is much closer to VRAM than DRAM due to its advanced design. SGRAM is typically used in moderate to high-end cards where performance is important but the very highest resolutions are not required. Matrox Graphics is probably the company best-known for making extensive use of SGRAM.