MSI Z77MA-G45 can't change CPU voltage

TheDoubleD

Honorable
Apr 6, 2013
15
0
10,510
Hello. So I have a MSI Z77MA-G45 motherboard and a i5 3570k CPU. I want to overclock it with a custom voltage setting, but I can't change it in the BIOS. At the CPU Voltage setting I have:

Auto
+0.020000 V
+0.040000 V
+0.060000V

And that's it, only 4 options. What does it mean? How to I change it, for example, to 1.1 V?

Screen of bios: http://i.imgur.com/tbLHQ8U.png