These modules are rated for operation at DDR3-1600 which is PC3-12800 at 1.8V. The modules have SPD values for lower speeds (DDR3-1066) at JEDEC specs to provide boards the needed initial boot to provide the RAM with the proper voltage and timings. The stock timings at DDR3-1600 are 8-8-8-24. DDR3 latencies are very high compared to DDR2 and should only get better in time. These modules are lead free which helps the environment. Nothing like being green in today's world. I almost forgot that the command rate is 1T which means you get an extra performance boost.