• Computer memory varies from motherboard to motherboard. The main reason for the differences in memory is because the slight changes in computer architecture can increase the importance of the memory. Another reason why the actual design of a memory card might change is so that if you upgrade your computer, you do not put the wrong card in a particular memory slot.
  
  

Rambus DRAM (RDRAM)

• RDRAM (Rambus Dynamic Random Access Memory) is not a common type of memory slot. This kind of memory sends data at 16-bit chunks, making it slightly unpopular in modern-day machines. The general demands of most applications require RAM to send data at a rate of at least 32-bit chunks, if not 64-bit. Although 16 bits is a slightly inconvenient data width, RDRAM can reach significant clock speeds. All memory slots that support RDRAM contain 184 pins. These slots are also classified as RIMM (Rambus Inline Memory Module) slots.
  
  

Synchronous DRAM (SDRAM)

• Personal computers that were created since 1996 generally contain single-data-rate SDRAM. Around 2004, this kind of RAM began to become obsolete with the advent of its successor: DDR (Double Data Rate SDRAM). Conventional SDRAM slots contain 168 pins. Its data bandwidth can approach speeds of up to 1 GBs, depending on what the motherboard is compatible with. Slower cards can work on faster slots and vice versa.
  
  

DDR (Double Data Rate SDRAM)

• DDR is the successor of the long-standing SDRAM. DDR can perform twice as fast as SDRAM because it can send and receive data on both the "crest" and "trough" of each of the processor's clock vibrations. This essentially duplicates the amount of data that can be processed in a certain amount of time, hence the term "double data rate," A DDR slot has 184 pins, and its data delivery speed can reach up to 6.4 GBs.
  
  

DDR2

• The need for faster RAM by demanding applications resulted in the development of DDR2, which allows memory to be transferred at up to 8.5 GB per second. DDR2 also performs very efficiently with 64 bits of data width, making it ideal for modern computing systems that make use of such a feature.