EDO RAM

Unlike FPM RAM, when EDO RAM locates memory, it does not wait until one memory cell has been located and read before beginning the process of accessing the next. EDO RAM improves upon FPM RAM by beginning its search for memory at the point where the last piece of memory is found. Because large chunks of memory are written at the same time, related data points are usually written next to one another. EDO RAM takes advantage of this.

EDO RAM is like FPM RAM in that it must be power-refreshed before any memory can be read. Each cell in EDO RAM is made up of a transistor and a capacitor. To read data, the CPU sends a signal to the RAM controller, which then forwards the request to the appropriate memory cell. If the charge in the capacitor is above a certain voltage level, the cell is read as a 1; if it is below that voltage level, the charge is read as a 0. In order for the charge reading to be valid, a power-refresh is necessary.

When to Use EDO RAM

Check your computer's manual to see if it supports EDO RAM. If so, upgrading your memory can give you a significant boost in performance. If deciding between FPM RAM and EDO RAM, EDO is the clear winner--EDO processes up to 40 percent faster than Fast Page Memory.

Despite its excellent performance when it was introduced, newer RAM types have since replaced EDO. SDRAM and DDR have dropped considerably in price and due to their increased performance have supplanted EDO RAM as the industry standard. This is typical of the memory industry, as memory manufacturers are constantly increasing the capabilities of RAM.