Calling any Nehalem owners

[ghost recon88]

I read at XS that there is a relationship between the QPI/DRAM voltage (also known as VTT or uncore voltage) and the VDIMM. This is where it becomes tricky apparently, the difference between the two cannot be > than 0.5 volts otherwise the CPU gets a hard knock

how much ICH and IOH does to OC stability if any?

Anyone have an answer or possible guess to these questions?