It really depends on what motherboard and CPU you are using it with. Both are overclocked DDR2 800. Standard DDR2 800 runs at 1.8v and cas 5 5 5 15. In the case of the Mushkin the extra volts allow faster timings and the GSkill raises clock speed the same way. I have Corsair that is 2.1v cas 4 4 4 12.