Core i7 Vdimm/VTT Graveyard :D

[Hondacity]

Has anyone killed a CPU by running 1.45 QPI 24/7?

thats normal, i'm using 1.7v on the qpi and it isn't dead yet

[Amurtigress]

Bei Fei, Hondacity,

you might want to have a look at post 223 that I just edited. It might shed some light on the whole matter of VDIMM....

[Amurtigress]

Hello, (continued from post #223)

I just realized that it would have another consequence if Intel really designed their CPUs to have the uncore powered by the same voltage as the DIMM sockets.

It would mean that the uncore/QPI voltage would always be the same as the standard JEDEC compliant voltage for normal DDR3 DIMMs. Namely, 1.5V!

As a consequence of this, we should probably do the following:

1) Start considering 1.5V to be the default voltage for the QPI/uncore part of our i7s. And thus stop wondering if any lower voltage than that could kill our precious chip.

2) Reconsider the voltages we use depending on the actual DDR3 clock rates we are torturing our uncores with.

So I am suggesting the following table for uncore/QPI:

DDR3 clock uncore voltage DIMM Voltage

1066 1.5V (JEDEC compliant) 1.5V
1333 1.5V (JEDEC compliant) 1.5V
1600 1.55V See specs of your modules but keep below 2V
1800 1.6V (suggested by Corsair for some of their products)
2000 1.65V

Certainly this has to be tested on any individual setup. And the fact that for example ASUS is defaulting to 1.2V for QPI doesn't make it correct. I rather see what Intel built the CPUs for and stick to that.

It might as well be possible that stable operation of the IMC below 1.5V is a design precaution by Intel to support future die-shrinked memory chips that will stick to upcoming JEDEC specifications, for example Samsung who announced 1.35V DDR3 chips. 1.35V uncore would be supported right away then.

Any thoughts? I hope I am not ridiculing myself here with such a theory.