You said that you can't push your QPI/DRAM any higher than 1.6 - 1.65v. But doesn't a R2E have some jumper you can switch to get the availability over higher voltage settings?

On my P6T Deluxe I know I have some jumpers I can switch to open up a higher voltage range for extreme overclocking of some components. Problem is I can't recall exactly which jumpers / components these are. Maybe only for increasing vcore and vmem. However a R2E has much wider range of settings, I guess so maybe your lucky and you have a jumper for increasing the QPI/DRAM voltage.