The Compatibility of RAM Upgrades

There are many varieties of RAM, and your computer may not support them all.

There are a number of factors that effect a RAM (random access memory) module's compatibility with a computer. When upgrading RAM, it's important to install modules (chips) that work with the computer in question. Otherwise the modules may go unrecognized by the system.

Pins

The primary factor in RAM compatibility is the number of pins on the chip. Pins are the gold leads located at the bottom of the module that serve to connect it to the motherboard's RAM socket. If the number of pins is incorrect, the module will not install.

Types

RAM can be static or dynamic, SDR (single data rate), DDR (double data rate), DDR2 (double data rate x2), or DDR3 (double data rate x3), DRAM (direct rambus), FPM (fast page mode) or EDO (extended data out). It's vital to check the manufacturer's specifications when purchasing RAM for your computer.

Speed

Most computers support various speeds of RAM. If you install chips with different speeds, they'll both run at the speed of the slower chip.

ECC or Buffered

Error correction code (ECC) RAM, also known as parity RAM, is intended for network servers. Buffered or registered RAM modules have additional chips that act as buffers to reduce errors. Not all motherboards support this type of RAM, so check the manufacturer's specifications before purchasing.

RAM Capacities

RAM capacities range from 8MB to 32GB. The amount of RAM your computer recognizes depends on your operating system (OS). If you have a 32-bit OS, it won't recognize more than 3.5GB. 64-bit versions, however, can use 32GB--or more--of RAM. If your computer uses a standard 32-bit OS, there's no need to install more than 4GB.

References

• PC Buyer Beware: Types of RAM Memory
• Tom's Hardware RAM Guide
• Crucial: FAQ: What is the difference between DDR3, DDR2, DDR, and SDRAM

Resources

• Whatis: RAM Defined