EDO memory modules

In 1995, EDO became the next memory innovation. It was similar to FPM, but with a slight modification that allowed consecutive memory accesses to occur much faster. It eliminates much of the wait time by cutting out a few steps in the addressing process allowing the processor to access data during the refresh cycle. In other words, the computer can load data as it is searching for new information. EDO memory is generally 10 to 20% faster than FPM memory. A computer must support EDO memory in order to notice an increase in performance. EDO RAM comes on a 72-pin SIMM (commonly found in older desktop computers, such as the 486 and early Pentium models), 144-pin SODIMM (commonly found in laptop computers) or 168-pin DIMM (commonly found in Pentium and Athlon systems). EDO RAM cannot operate on a bus speed faster than 66MHz. Extended data out (EDO) and fast page mode (FPM) memory modules are not interchangeable.

72-pin SIMM

How Many Modules Do You Need
How Much Memory Do You Need