AA32C12864-PC400 is an INDUSTRY STANDARD 1GB SDRAM DDR-400Mhz/PC3200 184-Pin DIMM for Desktops (HP, Dell, IBM/Lenovo, etc.). This memory module is built to JEDEC Standards. All Add-on memory products are 100% tested and 100% guaranteed to be compatible with the systems it is intended for.
From the Manufacturer
Double Data Rate (DDR) SDRAM memory is a product built upon the foundation of older PC100/PC133 memory technology. DDR SDRAM memory can do two operations per clock cycle, unlike SDRAM memory which only supports one operation per the computer’s clock cycle. By having DDR technology, you are doubling the memory bandwidth over the corresponding single-data-rate SDRAM.