You set it manually in your bios. My ram are rated as 1.65V but I manually changed it to 1.5v. I did drop the speed though because I need to overclock in order to reach 1600mhz. I believe that Z68 has higher memory standard.. you should check if you need to overclock. You can buy any ram preferably kingston and g.skill because they're cheaper and works as well as corsair.
(just one example of inexpensive, but good RAM. I think it's the Canada site; change to US if needed.)
Your BIOS should automatically apply all correct voltage and timings. The only exception to this rule is:
1. your present BIOS does not contain the profile for your RAM (update the BIOS if possible. it may have an updated RAM profile)
2. the voltage specs of the RAM are beyond what the motherboard can handle. Would they really make RAM that motherboards can't handle?
RAM can operate at different frequencies and voltage levels. If the BIOS is "smart" and can't support 1.65V then it should use a lower frequency and lower voltage.
*I would be surprised if your motherboard, using an updated BIOS did not apply the correct settings automatically for your RAM.
**Run Memtest to make sure things are okay.
***I discovered in an ASUS motherboard manual this:
"DIMM voltage below 1.65V is recommended to protect the CPU"