Memory Speed

For various technologies, there are certain bus and device clock frequencies that are standardized. There is also a decided nomenlature for each of these speeds for each type.

SDRAM
SDR SDRAM DIMMs - These first synchronous registered DRAM DIMMs had the same bus frequency for data, address and control lines.
 * PC66 = 66 MHz
 * PC100 = 100 MHz
 * PC133 = 133 MHz

DDR SDRAM (DDR1) SDRAM DIMMs
DIMMs based on Double Daqta Rate (DDR) DRAM have data but not the strobe at doubt the rate of the clock. THis is achieved by clocking on both the rising and falling edge of the data strobes.
 * PC1600 = 200 MHz data & Strobe / 100 MHz clock for address and control.
 * PC2100 = 266 MHz data & Strobe / 133 MHz clock for address and control.
 * PC2700 = 333 MHz data & Strobe / 166 MHz clock for address and control.
 * PC3200 = 400 MHz data & Strobe / 200 MHz clock for address and control.

DDR2 SDRAM DIMMs
DIMMs based on Doube Data Rate 2 (DDR2) DRAM also have data and data strobe frequencies at double the rate of the clock. This is achieved by clocking on both the rising and falling edge of the data strobes. The power consumption and voltage of DDR2 is significantly lower than DDR1 at the same speed.
 * PC2-3200 = 400 MHz data & Strobe / 200 MHz clock for address and control.
 * PC2-4200 = 533 MHz data & Strobe / 266 MHz clock for address and control.
 * PC2-5300 = 667 MHz data & Strobe / 333 MHz clock for address and control.
 * PC2-6400 = 800 MHz data & Strobe / 400 MHz clock for address and control.
 * PC2-8000 = 1000 MHz data & Strobe / 500 MHz clock for address and control.
 * PC2-8500 = 1066 MHz data & Strobe / 533 MHz clock for address and control.
 * PC2-9600 = 1200 MHz data & Strobe / 600 MHz clock for address and control.

DDR3 SDRAM DIMMs
DIMMs based on Doube Data Rate 3 (DDR3) DRAM also have data and data strobe frequencies at double the rate of the clock. This is achieved by clocking on both the rising and falling edge of the data strobes. The power consumption and voltage of DDR3 is significantly lower than DDR2 at the same speed.
 * PC3-6400 = 800 MHz data & Strobe / 400 MHz clock for address and control.
 * PC3-8000 = 1000 MHz data & Strobe / 500 MHz clock for address and control.
 * PC3-10600 = 1333 MHz data & Strobe / 667 MHz clock for address and control.
 * PC3-12800 = 1600 MHz data & Strobe / 800 MHz clock for address and control.
 * PC3-16000 = 2000 MHz data & Strobe / 1000 MHz clock for address and control.