Upgrade Your Vintage PC with SIMM EDO DRAM Computer Memory

A fact of life when dealing with any computer from a particular time or era is that the memory standard it uses is tied to the said era. For example, Pentium and 486 PCs are compatible with SIMM memory only, which was the standard used at the time of their release. RAM must communicate closely with the processor, which is why memory standards evolve along with rapid improvements in data processing.


  • SIMM: This stands for "single in-line memory module," a type of RAM predominant during the early 1980s to the late 1990s. It is the predecessor of DIMM or dual inline memory modules and could only perform one operation per clock cycle. Early PCs would use socketed DIP (dual inline-package) chips for DRAM, which took a lot of motherboard space to upgrade. SIMM improved that by requiring just one additional RAM stick for an upgrade instead of nine single DIP chips.
  • PIN Variety: While 30-pin SIMMs come in standard sizes of 256 KB, 1 MB, 4 MB and 16 MB sticks, 72-pin SIMMs come in 1 MB, 2 MB, and 4 to 64 MB sizes
  • EDO: EDO stands for extended data out, which is also called Hyper Page Mode enabled DRAM. It is up to 30 percent faster than older Fast Page Mode (FPM) DRAM and replaced the latter standard in 1995. FPM and EDO DRAM were interchangeable components in many applications despite the performance differences.
  • DRAM: This acronym stands for dynamic random-access memory and is a random access semiconductor memory in tiny capacitors within an integrated circuit. These sticks contain soldered memory chips with varying architectures. It is considered volatile memory, which is a type of memory that loses its data quickly when power is removed. This is one of the reasons why a backup battery is necessary for important applications.

How to Install SIMM EDO RAM

  • Compatibility: Determine whether or not your computer motherboard can accept EDO RAM. This is found on the spec sheet of your computer or its motherboard. You can also inspect the circuit board along the sides of the motherboard. On it should be printed "EDO CAPABLE." This means that the motherboard may be able to take both FPM and EDO memory as options.
  • Removal: Remove the old SIMM modules by pushing down on the side thumb pins. This opens the fasteners and ejects the module from the SIMM slot through a spring mechanism that tips it sideward. This system ensures that an improperly inserted module is apparently visible to you.
  • Installation: To install a SIMM EDO module, press the module down into the slot so the terminals are aligned, and gently but steadily push the module forward against the fasteners to clip it in place. Repeat for the rest of the modules.