DDR3L memory modules resolve the embedded computer double refresh rate requirement by selecting the lowest total electrical current, incorporating thermal-relief copper pour methodology PCB design, reducing chip count, and utilizing 1.35 V DDR3 Dynamic Random-Access Memory (DRAM). Compared to current DDR3 designs, DDR3L memory can save up to +10 °C per module and remove the double refresh rate requirement. DDR3L VLP memory embedded computer module helps improve airflow and provides a low profile, allowing OEMs to offer higher-reliability products that reduce total cost of ownership. Specific DDR3L VLP modules also offer single refresh rates, which are now essential to maximize performance in high-temperature systems.
refer to : http://embedded-computing.com/articles/ruggedization-memory-module-design/