There's no need to make 3 threads asking pretty much the same question.
http://www.tomshardware.com/answers/id-3561406/memory-voltage-support.html
http://www.tomshardware.com/answers/id-3561400/ram-7500.html
If your RAM is rated for 1.2V, it will run at 1.2V be default, you don't have to change anything. As I told you in one of your other threads, 1.35V is just the
maximum for your CPU. It's not that the CPU expects or needs exactly 1.35V memory voltage to work. However, it's probably a good idea to enable the XMP profile. To do this, entire BIOS, look for memory settings or similar (or possibly under frequency settings), look for a field referring to memory profile or XMP. Select the profile that corresponds the memory speed that your RAM is rated for.