Many people know just what they want when building a new system, or upgrading an existing system. They pick out the perfectly matching CPU, motherboard and the video card combination of their preference, but when it comes to the memory, they simply have no idea, and much less of what DDR memory is. If you are one of such people, then here is all about the DDR memory that you need to know.

Why choose DDR memory?

DDR (double data rate) is an evolutionary memory technology based on SDRAM. The DDR SDRAM access is twice as fast as SDRAM, as data transfers occur on both edges of the clock. It is fast, transferring data up to 2133MB/s. It also consumes less power than the conventional SDRAM or other types of memories, with an operational Vcc of just 2.5Vcc instead of 3.3Vdc for SDRAM.

Which DDR do you buy?

Depending on your preference and your system, you can get any of the DDR memory available in the market (DDRI, DDR2 or DDR3). Selecting the right DDR variant is a very important factor in determining the overall performance of your system.

DDR1 memory

DDR1 is available as registered or unbuffered. DDR1 has its address and control lines buffered to reduce signal loading, and is more expensive than unbuffered DDR1. Unbuffered DDR1 does not feature address lines and control line buffering, so it cost less. Unlike the registered DDR1, unbuffered DDR1 can only be installed on one mother board to a maximum of 4 * 1GB.

DDR2 memory

This is the second generation DDR memory. While the 400MHz is the highest speed for DDR1, it is the lowest for DDR2. This means that DDR2 picks up where DDR1 leaves off. Due to the different latencies, a 400MHz DDR1 may outperform a 400MHz DDR2, but the advantage returns to DDR2 as soon as the speed reaches the next step (532MHz) which DDR1 can not reach.

DDR3 Memory

This is the third generation of the DDR memory. It begins with a speed level of 800Mbps (400MHz) as the lowest available. Today, the highest popularly available DDR3 speed runs at two billion data transfers per second.

DDR memory compatibility

It's not advisable to just walk into a shop and buy any DDR available for your system. You must consider the compatibility of the DDR memory. You can use the memory selector to find compatible DDR, DDR2 or DDR3 memory upgrades, or the all new system scanner to scan your system for the matching DDR memory.

What to consider when choosing DDR memory

Besides the compatibility, you need to check the different latencies in the market, compare different brands available and their prices and other factors that will be of preference to you.