DDR Memory Upgrade

DDR Memory Upgrade: "What is the difference between DDR SDRAM and SDRAM?

Most desktops and laptops use one of the two most popular types of synchronous dynamic random access memory (SDRAM) for the main system memory. Single data rate (SDR) SDRAM is the older type of memory, commonly used in computers prior to 2002. The more current type of memory, double data rate (DDR) SDRAM hit the mainstream computer market around 2002 and can be found in most new computers.
DDR SDRAM is a straightforward evolution from SDR SDRAM. The big difference between DDR SDRAM and SDR SDRAM is that DDR reads data on both the rising and falling edges of the clock signal, so the DDR module can transfer data twice as fast as SDR SDRAM.
Generally speaking, motherboards are built to support one type of memory. You cannot mix and match SDRAM or DDR memory on the same motherboard in any system. They will not function and will not even fit in the same sockets. The right type of memory to use is the one that your computer takes! We always recommend that you use the Crucial Memory Selector to find exactly the right memory for your computer."