The following result is obtained by our Internet Research Algorithm: DDR stands for Double Data Rate. There is a digital signal in our computer which helps in the transmission of data. These signals have both higher and lower frequencies and data handled in higher frequencies only. But with the help of DDR, data and also be handled in lower frequencies as well. If your DDR RAM claims frequency of 1600 MHz it is actually just 800 MHz as it is also counting lower frequency as well because data can be handle in lower frequency also. Hence, your desktop system will show you just 800 MHz in it.