SD RAM refers to a type of ram that is not as fast as the industry standard today (DDR RAM) SD RAM has speeds of 66Mhz, 100Mhz, and 133Mhz where as DDR RAM has speeds that range from 200Mhz - ~500Mhz, they say that 256megs of SD Ram (133Mhz variety) is the same as having 128DDR RAM (266 Mhz...