types of ddr ram measured by SPEED MHZ

The types of  DDR RAM memory
Double Data Rate abbreviated DDR - Double data rate or DDR2 and are distinguished by the speed of operation (the higher the speed of operation and will decrease access times to memory to store and retrieve data, and then lower the waiting time for those who use the software).

types of  DDR RAM A memory to 333MHz has an access time of 6ns ( 6 billionths of a second ) by a 466MHz has an access time of 4.5 nS. Although these values ​​appear insignificant must multiply by the enormous amount of computation that has to travel at this time and here there can be very significant differences. The DDR has 184 pins (the "feet" golden connection on the motherboard) and types of  DDR RAM :
Speed ​​(MHz) Symbol
200 PC1600
266 PC2100
333 PC2700
400 PC3200
433 pc3500
466 PC3700
500 PC4000
533 PC4300
550 PC4400
566 PC4600
600 PC4800