184 Pin DIMM
DDR SDRAM is the newest of the memory types under development that will be available in the 184 Pin DIMM form factor. The principle difference between conventional SDRAM and DDR SDRAM is its ability to read/write data on both edges of a clock, therefore resulting in faster data transfer. DDR SDRAM will be available in two frequencies, 200Mhz and 266Mhz, and operational voltage is 2.5v. There is speculation (these have not been released to manufacturing as of this writing) that these modules will be available in both 64 bit and 72bit ECC configurations, with memory ranges of 64 megabytes through to 1 gigabyte. The DDR SDRAM chips used are of the TSOP package.