whats printed on your ram 1.5v or 1.65v? if 1.5v then set to 1.5v if 1.65v then set to 1.66v,trust me ive run my ram at 1.66v for 3 years and still working fine,as for qpi/vtt its fine at that, the more ram you have the more you will need,i use 1.32v qpi/vtt @4.2ghz with 6gb of ram so you will need more
i wouldnt tell you anything that would harm your pc
are you running now at 3.6ghz with those settings? and does cpu downclock at idle?