I was reading that maximum voltage for QPI/DRAM is 1.35, and that QPI/DRAM voltage should be within 0.3 v of CPU core voltage and within 0.5 of DRAM voltage, is this true? Can someone brief explain to me.
Yes it is true but only if you want to take the memory voltage above 1.65v otherwise it dont really matter.
I have posted on this same question before and I dont really have an explanation for it but this is the guy who said it.
Intel performance guru François Piednoel. Do a search on him and you will get what you are looking for.