CPU-z is showing that your RAM is running @800MHz. To achieve 1066MHz you will have to make some changes in the BIOS settings. Increasing the Front Side Bus is probably the easiest way, bump it up until the RAM shows 1066MHz - this will also OC your cpu. Then change your RAM settings to match the latencies on the stickers (e.g.,5-5-5-15) and the RAM voltage (e.g., 2.1V). Save and exit the BIOS. After your system restarts, CPU-z should should the new RAM freq (multiply the numbers by 2).