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Double Data Rate SDRAM

DDR/DDR2/DDR3 SDRAM

All types of DDR RAM are easily identified by the continuous contacts on each side, with only a single “keying” notch along the contacts edge. Below are some diagrams that show the outline and notch position for the different types of DDR RAM.

Desktop DDR Memory Comparison (from wikipedia)
Laptop SODIMM DDR Memory Comparison (from wikipedia)

  • Generic Name: The name that is often used for this type of memory
  • Industry Name: The official standards body name for this type of memory
  • RAM Speed: The effective speed at which this RAM operates … which will be a multiple of the Bus (FSB) speed
  • Peak Transfer Rate: The maximum Data Transfer Rate that could be possible under ideal conditions

DDR3 Memory

Generic Name Industry Name RAM Speed Peak Transfer Rate
DDR3-1600 PC3-12800 1600 MHz 12800 MB/s
DDR3-1333 PC3-10600 1333 MHz 10667 MB/s
DDR3-1066 PC3-8500 1066 MHz 8533 MB/s
DDR3-800 PC3-6400 800 MHz 6400 MB/s
  • Desktop Memory ⇒ 240 contact DIMM
  • Laptop Memory ⇒ 204 contact SODIMM
  • Notch position moved noticeably compared to DDR & DDR2

DDR2 Memory

Generic Name Industry Name RAM Speed Peak Transfer Rate
DDR2-1066 PC2-8500 1066 MHz 8533 MB/s
DDR2-800 PC2-6400 800 MHz 6400 MB/s
DDR2-667 PC2-5300 667 MHz 5333 MB/s
DDR2-533 PC2-4200 533 MHz 4266 MB/s
DDR2-400 PC2-3200 400 MHz 3200 MB/s
  • Desktop Memory ⇒ 240 contact DIMM
  • Laptop Memory ⇒ 200 contact SODIMM
  • Notch position moved only slightly compared to DDR

DDR Memory

Generic Name Industry Name RAM Speed Peak Transfer Rate
DDR-400 PC-3200 400 MHz 3200 MB/s
DDR-333 PC-2700 333 MHz 2700 MB/s
DDR-300 PC-2400 300 MHz 2400 MB/s
DDR-266 PC-2100 266 MHz 2100 MB/s
DDR-200 PC-1600 200 MHz 1600 MB/s
  • DDR Memory is sometimes referred to as DDR1
  • Desktop Memory ⇒ 184 contact DIMM
  • Laptop Memory ⇒ 200 contact SODIMM