I can confirm the exact same behaviour on my 3930K and DX79SI. However, I cannot provide an answer, other than to let you know "its not just you!"
Good to know, I'm not alone
What I don't understand: the core VID is a suggestion, how much voltage the cpu should use? Or is the VID like a threshold?
By setting the voltage manually to 1.25V i get a really nice overclock and a stable system (3 days of rendering on all cores, everything succeeded and was fast as hell D) but on idle the VID is lower than the core voltage. Does it mean, the cpu gets 1.25V on idle? Or does the VID throttle the voltages down to vaues like 0.85V?
Sorry for those questions, my last cpu was a phenom II and they don't have these values :$
We regret to inform you that since overclocking can result in data corruption and unreliable system behavior, the support we offer for your inquiry is limited. We recommend not overclocking at all to keep your processor under healthy conditions. Thank you for your understanding.
Okay then I'd like to ask more precise:
Which voltage do I have, when I set the core voltage manually to 1.25V? Will it stay at 1.25V all the time or does the board lower the voltage when the cpu is in an idle-state?
The Intel Extreme Tuning Utility says the voltage stays there, CPU-Z shows a "core VID" that lowers itself to 0.85V or something like that, when in idle-state.
This is very important for me because all I could find on the internet where people with mainboards from other manufacturers with very different settings.
This has been bugging me for quite some time. I did just notice the voltage test points on the board, I might get the multimeter out in the next few days and see if it is actually transitioning down to .8v
I have the Intel DX79SI too+ the 3930K. Mine is running at 4.60GHz and the RAM speed is 2133MHz. Intel's own OC settings set's the volt to 1.42 however, this is not near enough. After CTD with Battfield 3, I decided to run some test with IntelBurntest tool. http://www.xtremesystems.org/forums/showthread.php?197835-IntelBurnTest-The-new-stress-testing-program
This is not an Intel tool. With this it turns out, that I have to rise the volt to 1.47.
CPU-z does not show the volt max at 1.47, but at about 1.345 volt (full load)
Since then there has been no bsod or any other crash.
I ran the test 10 times at maximum. Link to volt settings: http://www.overclock.net/t/1326481/i7-3930k-voltage
I am on water cooling and have no issue with heat.
Once again, we recommend not overclocking at all to keep your processor under healthy conditions. Thank you for your understanding.
This is an official post. Hence, they can't support and/or supply you with a solution. If they do they will be held liable if something went wrong.
It's kinda weird how Intel has a big price tag on products with overclocking capabilities "e.g.. K series"
overvlock.net is a great site & http://www.overclockers.com are great also there is a guy named Dfonda. I highly advise you taking his instructions "great guy".
Here is what's confusing us. With Default CPU voltage plus an offset, the CPU will idle at around .8V. Great.
CPU sends VID of .8V and that's what it gets.
However, when you set the VCC voltage manually, ie 1.35v, its always at that, besides vdroop. At idle the VID as reported by CPUZ is .8v, but the motherboard still supplies 1.35v, for VCC. I've just confirmed that with a multimeter.
The problem is, when setting the voltage manually, there is no idle voltage. It would be fantastic if Intel somehow implemented this in the BIOS as an option. We don't need 1.35v going to the CPU all the time, only under load.
I know I can squeeze a lot more out of my CPU with a manual voltage, but I don't like the idea of it always operating at the specified voltage. Lets face it, its not too often that my PC goes to 100% utilization.
On mine, I can get about 4.2ghz with default voltage and an offset. I can go higher with a manual voltage. However, I want the CPU to idle at around .8 Volts, so I've left it as default + offset.
BTW, on these boards, CPU-Z only reports the voltage the CPU is requesting (VID), That is different to the voltage it is receiving (VCC). DONT rely on CPU-Z to measure CPU voltage.
Intel Desktop utilities and Extreme Tuning Utility will show correct VCC.
Maybe Intel will look into this and offer a update. That would be fantastic.
Thanks for your respons/explanation about VCC and VID volt.
This may be why many users/gamers believe that they are/can run there Intel oc cpu with 4.5-4.7 GHz at about 1.30-1.35 volt, because they are reading/looking at the VID volt only.
The 1.42 VCC volt Intel's own oc assist is using at 4.60GHz, is not enough for 100% stable gaming like Battlefield3.
Since the 3930K was released, AMD has push/optimized there GPU driver for higher fps in games, this fps increase does not come out of no where. The latest AMD GPU drivers are pushing/seeking more power out of the CPU.
When users/gamers wants to oc, it is recommended to run some stress test like IntelBurnTest, to ensure that the CPU gets the VCC it needs.
At 4.60 GHz my Intel 3930K needs 1.47 VCC volt.
At 4.70 GHz it needs 1.485 VCC volt.
BTW, I am very happy with my Intel 3930K and the Intel DX79SI, only sad thing is that Intel will stop producing their own motherboards.
Intel should reconsider and continue to produce their own motherboards for the Extreme series, like the DX79SI and DX79SR in the future too, and only stop the mainstream boards.