DDR-3 SDRAM or Double Data Rate type Three Synchronous Dynamic Random Access Memory is a successor to DDR & DDR2. As compared to DDR2 SDRAM, it has ability to transfer data at double rate; i.e., eight times the speed of its internal memory arrays; thus enabling higher bandwidth (peak data rates). It has two transfers per cycle of a quadrupled clock signal; that enables it to achieve a transfer rate of up to 64 times the memory clock speed. DDR3 SDRAM modules use DDR architecture to achieve high-speed operation. DDR3 architecture is basically an 8n-prefetch architecture which transfers two data words per clock cycle at the input-output pins. Initially it was launched with 1.5v DDR3 DRAM; later DDR3 DRAM works at 1.35v. 1.35v is usually compatible with all 1.5v platforms. Long-DIMM (or Desktop RAM) comprises of 240 connector pins, whereas SO-DIMM (Laptop RAM) comprises of 204 connector pins.