Computer Science

Different Types of Memory Packaging [Explained]

Memory is made from tiny semiconductor chips that are then packaged in a less fragile way to enable them to be integrated into a computer system. The chip packages are more often integrated into larger packages. Computer memory is therefore available in different types of memory packaging. This article discusses the various memory packaging that has been used in the computer world.

There are basically four different types of memory packaging. They are briefly explained below:-

4 Different Types of Memory Packaging

  1. DIP (Dual Inline Pin Package)
  2. SIPP (Single Inline Pin Package)
  3. SIMM (Single Inline Memory Module)
  4. DIMM (Dual Inline Memory Module)

1. DIP (Dual Inline Pin Package)

DIP (Dual Inline Pin Package) package comprises a rectangular chip with a row of pins down each long side, making it resemble an insect. DIP was the most common DRAM package used in PCs through early 386 models. DIP chips were produced in Page Mode and Fast Page Mode, and are long obsolete. DIP packaging was also used for L2 cache memory on most 486 and some Pentium-class motherboards. DIP DRAM is useless nowadays.

2. SIPP (Single Inline Pin Package)

SIPP (Single Inline Pin Package) turns a DIP chip on its side and extends all leads straight out one side, parallel to the plane of the chip. SIPPs were intended to allow memory to be installed more densely and were used in a few 386SX systems, but they never caught on. SIPPs were produced in Page Mode and Fast Page Mode form, and are long obsolete.

Single Inline Pin Package (SIPP) - Different Types of Memory Packaging

Single Inline Pin Package (SIPP)

3. SIMM (Single Inline Memory Module)

SIMM (Single Inline Memory Module) package mounts multiple individual DRAM DIP chips on a small circuit board with a card-edge connector designed to fit a socket on the motherboard. Mainstream SIMMs have been manufactured in two form factors:

  1. 30-pin
  2. 72-pin
Single Inline Memory Module (SIMM)

30-pin, Proprietary Apple 68-pin, and 72-pin SIMMs

i. 30-pin

These SIMMs were used in a few 286 systems, most 386 systems, and some 486 systems, and were produced in Page Mode and Fast Page Mode form. Although they are still available, 30-pin SIMMs are obsolete. If you tear down an old system, any 30-pin SIMMs you salvage are too small and too slow to be useful. However, some laser printers do use them.

ii. 72-pin

These SIMMs were used in some 386 systems, most 486 systems, and nearly all Pentium-class systems built before the advent of DIMMs. 72-pin SIMMs were produced in Fast Page Mode, EDO form, and BEDO form. When tearing down old systems, 72-pin SIMMs may be worth salvaging, as they can be used to expand the memory on a late-model Pentium or Pentium Pro system or to expand the memory in some laser printers.

4. DIMM (Dual Inline Memory Module)

DIMM (Dual Inline Memory Module) are dual-side modules that use connectors on both sides of the circuit board. SDR-SDRAM DIMMs have 168 pins, but SDR-SDRAM is also available in 100- and 144-pin DIMMs. DDR-SDRAM is packaged in 184-pin DIMMs, which are physically similar to standard 168-pin SDR-SDRAM DIMMs but have additional pins and different keying notch positions to prevent them from being interchanged.

Dual Inline Memory Module (DIMM)

Two types of DIMMs: a 168-pin SDRAM module (top) and a 184-pin DDR SDRAM module (bottom).

DDR-II DIMMs are similar to DDR DIMMs but use a 232-pin connector. Only SDR-SDRAM, DDR-SDRAM, and EDO are commonly packaged as DIMMs.

About the author

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Nikhil Agrawal

Nikhil Agrawal holds a Bachelor of Commerce (B.Com) degree and he loves to write how-to guides around Computer Fundamentals, Computer Software, Computer Programming, etc.