IMO, zoson's theory is most probably right, if not absolutely.

Quote Originally Posted by zoson View Post
So everyone knows... In case it wasn't common knowledge.

QPI PLL is linked to the CPU PLL setting in BIOS on the R3E.

I asked how it was controlled to ASUS techsupport and that's the answer I got.

I've asked them for a table of values showing what QPI PLL voltage is set per different CPU PLL settings.

It seems 1.89v CPU PLL is probably between 1.14 and 1.16v QPI PLL. Raising my CPU PLL to this value gives me about the same stability/voltage settings that I got on my friend's x58a-ud3r with my chip.
I think that QPI PLL loops 2-3 times from lowest to highest in one loop of CPU PLL voltage from 1.2V to 2.1V.
One thing is sure, QPI PLL is 1.1V when CPU PLL is 1.8V and probably when CPU PLL is lowest 1.2V QPI PLL is 1.1V or even 1.0V.

Could be something like this:
CPU PLL | 1.2 | 1.3 | 1.4 | 1.5 | 1.6 | 1.7 | 1.8 | 1.9 | 2.0 | 2.1 |
QPI PLL | 1.0 | 1.1 | 1.2 | 1.3 | 1.4 | 1.0 | 1.1 | 1.2 | 1.3 | 1.4 |

or maybe not so linear, IDK