There's a silent consent about vtt-vdimm ratio IMHO... i hear it alot in German forums. Truth is, there's an optimal distance between vdimm an vtt voltages, and it's to be kept for maintaining stability, speed and reliability of the memory system. Getting out of range too much either + or - results in bsods of 124 type, spontaneous reboots or plain instability.

My experiences have shown, that a difference between 200 and 240mV is optimal for my set of hypers and this 759 plus xeon cpu.


224mV^^


234mV^^

Vdimm has to be raised, even if there's no need to according to the great elpidas. That's just because vtt has to be increased exponentially - it seems - to maintain stability at high uncore clocks (1.324Vtt 4000 UC -> 1.46Vtt 4200 UC). You have to test it for yourself as hardware differs. Each board and set of ram is different, but you can take those values as a hint for what to try first. RTLs are directly coupled to this as well and have to be set up properly not to get hiccoughs.

Cheers,
Stefan. :cheers: