Improvements in silicon production processes have enabled a reduction in the core and I/O voltage for an incremental improvement in DDR3. Called “DDR3L” for Low Voltage, the new devices will operate from a single 1.35V rail, compared to the 1.5V of existing devices, resulting in a power savings of 20% in many mainstream applications.
These devices are intended to be compatible with existing 1.5V DDR3 systems and may operate without restriction in those applications. All JEDEC standard DDR3 memory modules include a Serial Presence Detect (SPD) device, an EEPROM readable over an SMbus, that informs the host system of the capabilities and characteristics of the module, including the supported supply voltages, so that system designs can be aware of and take advantage of the new DDR3L devices. The standard for module labels has been updated for consistency as well, with “PC3L” indicating end-user modules such as personal computers, and “EP3L” for modules targeted at embedded products.
“This announcement is consistent with trends in the industry to gracefully migrate mainstream devices to lower power as new fabrication geometries permit the lower supply voltages,” said Joe Macri of AMD, chairman of the JC-42.3 memory committee. “This committee intends to continue evaluating proposals for further VDD reductions in the future, possibly 1.25V or even lower. We hope that System designers will consider making their system designs flexible to take advantage of lower VDD options in the future.”