DDR SDRAM - Learn and compare before you buy memory

Welcome to DDR SDRAM

 

DDR SDRAM supplies you with concise computer memory information. Before you go to buy the DDR SDRAM you were looking for, learn about the particular types, compare qualities and ensure compatibility.

Browse a certain category to learn more about that type of DDR SDRAM.

By amount (MB / GB) 1GB 512MB 256MB 128MB

By speed (MBps) PC3200 PC2700 PC2100 PC1600

By frequency (MHz) DDR400 (200MHz) DDR333 (166MHz) DDR266 (133MHz) DDR200 (100MHz)

The speeds and frequencies mentioned above are the ones standardized by JEDEC, the organization that produces specifications for DDR SDRAM. Some manufacturers optimize chips in order to produce other levels, such as: PC2400 DDR300 (150MHz), PC3000 DDR366 (183MHz), PC3500 DDR433 (216MHz), PC3700 DDR466 (233MHz), PC4000 DDR500 (250MHz), and PC4300 DDR533 (266MHz).

Additionally, memory can sometimes be run at above or below its standard speeds, practices which are known respectively as overclocking or underclocking (sometimes called "downclocking").

Other amounts of DDR SDRAM are also achieved by combining two, or in some cases three, chips into the memory slots on a computer's motherboard. 2GB, 768MB, and 384MB are a few common amounts of RAM from chip combinations.

About these numbers:

MB: megabytes (capacity)
GB: gigabytes (capacity)
MBps: megabytes per second (transfer speed)
MHz: megahertz (frequency)
PCxxxx: the number refers to the MBps
DDRxxx: the number refers to the MHz of front side bus (FSB), typically double of memory MHz