DDR3 Modules are not backwards compatible with DDR2 Modules
Inserting a DDR3 module into a DDR2 socket can damage the DIMM and/or the motherboard
DDR3 SDRAM is an improvement over its predecessor, DDR2 SDRAM.
The primary benefit of DDR3 is the ability to transfer twice the data rate of DDR2
DDR3 memory provides a reduction in power consumption of 30% compared to DDR2 modules
due to DDR3's 1.5V supply voltage, compared to DDR2's 1.8V