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Title: EDO, SGRAM and VRAM Post by Pete Finnigan on Aug 6th, 2009, 11:55am EDO (extended data output): EDO (extended data output) RAM is a type of random access memory (RAM) chip that improves the time to read from memory on faster microprocessors such as the Intel Pentium. EDO RAM was initially optimized for the 66 MHz Pentium. For faster computers, different types of synchronous dynamic RAM (SDRAM) are recommended. Synchronous Graphics RAM (SGRAM): Synchronous Graphics RAM (SGRAM) is clock-synchronized random access memory that is used for video memory. It is relatively low-cost video memory. It uses masked write, which enables selected data to be modified in a single operation rather as a sequence of read, update, and write operations. It also uses block write, which allows Web Design Company data for background or foreground image fills to be handled more efficiently. SGRAM is single-ported. Its special features are what make it a moderately fast form of video memory. The Matrox Mystique is an example of a video card that uses SGRAM. Video RAM (VRAM): Video RAM (VRAM) means in general all forms of random access memory (RAM) used to store image data for a computer display. All types of video RAM are special arrangements of dynamic RAM (DRAM). Video RAM is really a buffer between the computer processor and the display and is often called the frame buffer. When images are to be sent to the display, they are first read by the processor as data from some form of main (non-video) RAM and then written to video RAM. From video RAM (the frame buffer); the data is converted by a RAM digital-to-analog converter (RAMDAC) into analog signals that are sent to the display presentation mechanism such as a cathode ray tube (CRT). Usually, video RAM comes in a 1 or 2 megabyte package and is located on the video adapter card in the computer. Most forms of video RAM are dual-ported, which means that while the processor is writing a new image to video RAM, the display is reading from video RAM to refresh its current display content. The dual-port design is the main difference between main RAM and video RAM. |
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