I too am interested about this question and have been trying to source lowest power memory for my new laptop (Lenovo X220, i5 sandy bridge). After tweaking (BIOS, services, device manager, drivers, etc.) the laptop idles at 6-8 watts (backlight at minimum useable levels), so saving even a watt would bring > 10% power savings.
I have found two available DDR3 offerings claiming lower power:
1. Samsung 40nm DDR3 SO-DIMM memory
Claim: "Thanks to 40-nanometer technology, Samsung DDR3 uses up to 47 percent less power than traditional 60-nanometer memory. In addition, the product operates at a voltage as low as 1.35V to reduce its overall power demands and increase laptop battery life."
- Modules as still 1.5V, altough 1.35V models are coming according to
Samsung spec sheet. It is hard to say if the 47 percent savings were achieved with 1.5V memory (or true at all)
- Lower power consumption supposedly comes from 40nm process, so no BIOS support need
- price: about 50 usd / 4gb
2. A-DATA XPG Gaming Series DDR3 SO-DIMM
Claim: "The XPG DDR3L 1600G SO-DIMM runs at low operating voltage of 1.35 volts for reduced power consumption and extension of the laptop's battery life for longer mobile computing."
- Memory uses 1.35V voltage (DDR3L). I think it is probable that you would need BIOS support to use the unusual voltage. A-Data answered my query with the following: "most newer motherboards should be able to detect the SPD/XMP profiles to run at the proper voltage"
- These can be purchased in Europe from Pixmania for about 54 euros / 4GB.
Conclusion:
There are at least two brands on the market with lower power DDR3 memory for laptops. These modules are more expensive than normal modules and not nearly as widely available. I have not found any reviews testing these power savings claims, however in desktop DDR3 the
savings are real and measured in watts. As mentioned above, using only one stick of memory gives the greatest benefit: 1x4GB uses significantly less power than 2x2GB.
Any insight in the matter would appreciated.