It's been a while (Q2, 2004) since first DDR2 modules landed in customers' motherboards. Today, most if not all modern platforms come equipped with these chips. Note that all memory standards have to be first approved by JEDEC. First company to propagate the use of DDR2 memory was Intel with their Prescott CPUs, AMD followed later on with AM2. As of now, every major IC company seems to be holding on to DDR2 bandwagon. While DDR2 modules come in different speeds (533, 667, 800 and 1066 MHz) most of us -- especially enthusiasts, want to grab the fastest ones available on the market. There are still a lot of chipsets supporting memory up to 667 MHz DDR2. The newer ones cope with speeds of 800 MHz and beyond -- that's why the varation in speed.



Link: Bjorn3d