The DDR RAM memory modules are suitable for a wide range of older desktop computers. The original computer memory modules, the DDR SDRAM are available in single and dual (each consisting of two matched DDR modules) kits. The speeds of our DDR RAM modules range from PC2100 (266MHz) to PC4500 (566MHz). Having 184 pins and operating at a standard of 2.5V, our DDR SDRAM modules vary in capacity from 256MB to 2GB. Manufactured by leading brands such as Transcend, Adata, G.Skill, Team, and Patriot the quality is assured, and most of our modules are backed by a lifetime warranty.